#include <iostream>
#include <fstream>
#include <bits/stdc++.h>
#include <map>
#define pb push_back
#define ll long long
#define pii pair<int,int>
#define pll pair<long,long>
using namespace std;

int rez;
vector<string> ans;
vector<string> v;
int dp[28];
int i,j,k,index=0,firstcount=0;
vector<vector<string> > mat;

template <typename Out>
void split(const std::string &s, char delim, Out result) {
    std::istringstream iss(s);
    std::string item;
    while (std::getline(iss, item, delim)) {
        *result++ = item;
    }
}
std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    split(s, delim, std::back_inserter(elems));
    return elems;
}

int st,dr,maxim;
int lastst[20010],lastdr[20010];
int main()
{

    ifstream fin("text3.in");
    ofstream fout("text3.out");
    string t;
    v.pb(" ");
    int poz;
    while(fin>>t)
    {
        int len=t.length();
        firstcount++;
        v.pb(t);
        st=v[firstcount][0]-'a';
        dr=v[firstcount][len-1]-'a';
        if(dp[st]+1>dp[dr])
        {
            dp[dr]=dp[st]+1;
            lastdr[i]=lastst[st];
            lastst[dr]=i;
            if(dp[dr]>maxim)
            {
                maxim=dp[dr];
                poz=i;
            }
        }
    }
    rez=maxim;
    fout<<firstcount<<"\n";
    fout<<firstcount-rez<<"\n";
    ans.pb(" ");
    while(poz)
    {
        ans.pb(v[poz]);
        poz=lastdr[poz];
    }
    for(i=rez;i>=1;i--)
    {
        fout<<ans[i]<<"\n";
    }
    fin.close();
    fout.close();
    return 0;
}