#include <string>
#include <vector>
#include <list>
#include <algorithm>
#include <map>
#include <set>
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

class DP {
  public:
    string s, t;
    int F(int si, int ti);
    vector < vector <int> > Cache;
};
    
int DP::F(int si, int ti)
{
  int a1, a2;
  char a, b;

  if (si == s.size() || ti == t.size()) return 0;
  if (Cache[si][ti] != -1) return Cache[si][ti];

  a = s[si];
  b = t[ti];
  if (a > b) {
    a1 = F(si, ti+1);
    a2 = 1 + F(si+1, ti);
  } else {
    a1 = 2 + F(si, ti+1);
    a2 = F(si+1, ti);
  }
  Cache[si][ti] = ( (a1 > a2) ? a1 : a2 );
  return Cache[si][ti];
}

main()
{
  DP dp;
  int i;

  if (!(cin >> dp.s >> dp.t)) exit(1);

  dp.Cache.resize(dp.s.size());
  for (i = 0; i < dp.Cache.size(); i++) {
    dp.Cache[i].resize(dp.t.size(), -1);
  }

  printf("%d\n", dp.F(0, 0));
}