#include <iostream>
#include <string>

using namespace std;

int main()
{
  string saaa1,s2aa,asdasd;
  int ** Lasdfas,i,j,m,n;

  getline(cin,saaa1, ' ' );
  getline(cin,s2aa);

  m  = saaa1.length();
  n  = s2aa.length();

  Lasdfas = new int * [m + 1];
  for(i = 0; i <= m; i++) Lasdfas[i] = new int[n + 1];

  for(i = 0; i <= m; i++) Lasdfas[i][0] = 0;
  for(j = 0; j <= n; j++) Lasdfas[0][j] = 0;
  for(i = 0; i < m; i++)
    for(j = 0; j < n; j++)
      if(saaa1[i] == s2aa[j])
        Lasdfas[i + 1][j + 1] = 1 + Lasdfas[i][j];
      else
        Lasdfas[i + 1][j + 1] = max(Lasdfas[i + 1][j],Lasdfas[i][j + 1]);


  asdasd = ""; i = m - 1; j = n - 1;
  while((i >= 0) && (j >= 0))
    if(saaa1[i] == s2aa[j])
    {
      asdasd = saaa1[i] + asdasd;
      i--; j--;
    }
    else if(Lasdfas[i + 1][j] > Lasdfas[i][j + 1]) j--;
    else i--;
  cout << Lasdfas[m][n];
  return 0;
}