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/* BISMILLAHIR RAHMANIR RAHIM  */

#include<bits/stdc++.h>
#include<cstdio>
#include<sstream>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<algorithm>
#include<set>
#include<queue>
#include<stack>
#include<list>
#include<iostream>
#include<fstream>
#include<numeric>
#include<string>
#include<vector>
#include<cstring>
#include<map>
#include<iterator>

using namespace std;

#define READ                freopen("in.txt", "r", stdin)
#define WRITE               freopen("out.txt", "w", stdout)
#define ll                  int long long
#define ull                 unsigned long long
#define ld                  long double
#define lld                 long long double
#define pi                  acos(-1)
#define pb                  push_back
#define pff                  push_front
#define pbk                 pop_back
#define pfk                 pop_front
#define m_p                 make_pair
#define gcd(a,b)            __gcd(a,b)
#define lcm(a, b)        ((a)*((b)/gcd(a,b)))
#define INF                 1000000000
#define M                   1000000000+7
#define dist(ax,ay,bx,by)   ((ax-bx)*(ax-bx)+(ay-by)*(ay-by))
#define sf(a)            scanf("%d",&a)
#define sfl(a)           scanf("%lld",&a)
#define sff(a,b)         scanf("%d %d",&a,&b)
#define sffl(a,b)        scanf("%lld %lld",&a,&b)
#define sfff(a,b,c)      scanf("%d %d %d",&a,&b,&c)
#define sfffl(a,b,c)     scanf("%lld %lld %lld",&a,&b,&c)
#define loop(i,n)        for(ll i=0;i<n;i++)
#define loop1(i,n)       for(ll i=1;i<=n;i++)
#define pf               printf
#define ff               first
#define ss               second
#define SZ(a)            (int)a.size()
#define TEST_CASE(t)     for(int z=1;z<=t;z++)
#define PRINT_CASE       printf("Case %d: ",z)

/*----------------------Graph Moves----------------*/
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
/*------------------------------------------------*/

/*-----------------------Bitmask------------------*/
//int Set(int N,int pos){return N=N | (1<<pos);}
//int reset(int N,int pos){return N= N & ~(1<<pos);}
//bool check(int N,int pos){return (bool)(N & (1<<pos));}
/*------------------------------------------------*/

int a[10],b[10],c[10];
vector<pair<int,int> >v;
vector<int>s,e;
//vector<pair<int,char> >an;
int main()
{
    int n,x,y,p,r;
    char q;
    sf(n);
    for(int i=0;i<n;i++){
        sff(x,y);
        a[x]++;
        a[y]++;
        if(x==y) c[x]++;
        v.pb(m_p(x,y));
    }
   // sort(e.begin(),e.end());
    for(int i=1;i<=6;i++){
        if(a[i]%2==1){
            s.pb(i);
        }
    }
   // cout<<s.size()<<endl;
    if(s.size()==2){
        if(c[s[0]]>0){
            cout<<s[0]<<endl;
            for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(x==s[0] && y==s[0]){
                pf("%d a\n",i+1); c[x]--;
            b[i]=1;r=y;
            break;
            }
            }
        }
        else{
        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(s[0]==x){
                b[i]=1;
                pf("%d a\n",i+1);
                r=y;
                break;
            }else if(s[0]==y){
                b[i]=1;
                pf("%d b\n",i+1);
                r=x;
                break;
            }
        }
        }
        if(c[s[1]]>0){
            for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(x==s[1] && y==s[1] && b[i]==0){
                p=i+1;b[i]=1;c[x]--;
                q='a';break;
            }
            }
        }
        else{

        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(x==s[1] && b[i]==0){
                p=i+1;b[i]=1;
                q='a';break;
            }else if(s[1]==y && b[i]==0){
                p=i+1;b[i]=1;
                q='b';break;
            }
        }
        }
        A:
            int i=0;
        if(c[r]>0){
            for( i=0;i<n;i++){
                x=v[i].ff,y=v[i].ss;
                if(x==r && y==r && b[i]==0){
                    r=y;c[x]--;
                    b[i]=1;
                    pf("%d a\n",i+1);
                    break;
                }
            }
        }
        else if(i==n || c[r]==0){
        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(b[i]==0 && r==x){
                b[i]=1;
                pf("%d a\n",i+1);
                r=y;
                break;
            }
            else if(r==y && b[i]==0){
                b[i]=1;
                pf("%d b\n",i+1);
                r=x;
                break;
            }
        }
        }
        for(int i=0;i<n;i++){
            if(b[i]==0) goto A;
        }
        pf("%d %c\n",p,q);
    }
    else if(s.size()==1){
        if(c[s[0]]>0){
            for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(x==s[0] && y==s[0])
                pf("%d a",i+1);c[x]--;
            b[i]=1;
            break;
            }
        }
        else{
        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(s[0]==x){
                b[i]=1;
                pf("%d a\n",i+1);
                r=y;
                break;
            }else if(s[0]==y){
                b[i]=1;
                pf("%d b\n",i+1);
                r=x;
                break;
            }
        }
        }
        B:
            int i=0;
            if(c[r]>0){
            for(i=0;i<n;i++){
                x=v[i].ff,y=v[i].ss;
                if(x==r && y==r && b[i]==0){
                    r=y;c[x]--;
                    b[i]=1;
                    pf("%d a\n",i+1);
                    break;
                }
            }
        }
        else if(i==n || c[r]==0){
        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(b[i]==0 && r==x){
                b[i]=1;
                pf("%d a\n",i+1);
                r=y;
                break;
            }
            else if(r==y && b[i]==0){
                b[i]=1;
                pf("%d b\n",i+1);
                r=x;
                break;
            }
        }}
        for(int i=0;i<n;i++){
            if(b[i]==0) goto B;
        }
    }
    else{
        b[0]=1;
        pf("1 a\n");
        r=v[0].ss;
        C:
            int i=0;
        if(c[r]>0){
            for( i=0;i<n;i++){
                x=v[i].ff,y=v[i].ss;
                if(x==r && y==r && b[i]==0){
                    r=y;c[x]--;
                    b[i]=1;
                    pf("%d a\n",i+1);
                    break;
                }
            }
        }
        else if(i==n || c[r]==0){
        for(int i=0;i<n;i++){
            x=v[i].ff,y=v[i].ss;
            if(b[i]==0 && r==x){
                b[i]=1;
                pf("%d a\n",i+1);
                r=y;
                break;
            }
            else if(r==y && b[i]==0){
                b[i]=1;
                pf("%d b\n",i+1);
                r=x;
                break;
            }
        }
        }
        for(int i=0;i<n;i++){
            if(b[i]==0) goto C;
        }

    }
}
/*
6
5 1
4 4
5 4
2 3
3 1
2 2
*/