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

int F(string s, string t)
{
  char a, b;
  string x, y;
  int a1, a2;

  if (s.size() == 0 || t.size() == 0) return 0;
  a = s[0];
  x = s.substr(1);
  b = t[0];
  y = t.substr(1);
  if (a > b) {
    a1 = F(s, y);
    a2 = 1 + F(x, t);
  } else {
    a1 = 2 + F(s, y);
    a2 = F(x, t);
  }
  return (a1 > a2) ? a1 : a2;
}

main()
{
  string s1, s2;

  if (!(cin >> s1 >> s2)) exit(1);
  printf("%d\n", F(s1, s2));
}