lcs

#include<bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef pair<ll,ll> pll;
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL))
#define fi first
#define se second
#define pb push_back
ll const MOD=1000000007;
const int M= 1e5 +10;
#define eb emplace_back
ll ara[100][100];
string a,b;
void lcs(int n, int m )
{

   for(ll i=1;i<=n;i++)
   {
       for(ll j=1;j<=m;j++)
       {
           if(a[i]==b[i])ara[i][j]=1+ara[i-1][j-1];
           else ara[i][j]=max(ara[i-1][j],ara[i][j-1]);
       }

   }

   cout<<ara[n][m]<<endl;

     int i=n, j=m;

   while (i > 0 && j > 0)
   {
       cout<<i<<" "<<j<<endl;

  cout<<a[i-1]<<" "<<b[j-1]<<endl;

      if(a[i-1]==b[j-1])
      {
       cout<<a[i-1]<<endl;;
          i--; j--;

      }

      else if (ara[i-1][j] > ara[i][j-1]) i--;

      else
         j--;
   }





}






int main()
{



   cin>>a>>b;


   ll n=a.size();
   ll m=b.size();

   lcs(n,m);








}