#include <iostream>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <vector>
using namespace std;

class Subseq {
  public:
    string s1, s2;
    vector < vector <int> > cache;
    int MCS();
};

int Subseq::MCS()
{
  int r1, r2, i1, i2;
  size_t i;

  /* Create the cache, and fill it with zero's. 
     You'll note that cache[i][s2.size()] and cache[s1.size()][i] should equal zero,
     so we don't have to calculate them. */

  cache.resize(s1.size()+1);
  for (i = 0; i < cache.size(); i++) cache[i].resize(s2.size()+1, 0);

  /* Now start with i1 and i2 being s1.size()-1 and s2.size()-1 respectively, and 
     fill in the cache from high to low.  */

  for (i1 = (int) s1.size()-1; i1 >= 0; i1--) {
    for (i2 = (int) s2.size()-1; i2 >= 0; i2--) {
      if (s1[i1] == s2[i2]) {
       cache[i1][i2] = 1 + cache[i1+1][i2+1];
      } else {
        r1 = cache[i1][i2+1];
        r2 = cache[i1+1][i2];
        cache[i1][i2] = (r1 > r2) ? r1 : r2;
      }
    }
  }

  /* The final answer is in cache[0][0]. */

  return cache[0][0]; 
}

int main(int argc, char **argv)
{
  Subseq ss;

  if (argc != 3) {
    cerr << "usage: subseq s1 s2\n";
    exit(1);
  }

  ss.s1 = argv[1];
  ss.s2 = argv[2];

  cout << ss.MCS() << endl;
  return 0;
}