// Advanced Algorithms - Chapter 14.
#include <iostream>
#include <vector>
#include <limits>
#include <algorithm>
#include <cstdio>

// Distance de Levenshtein
// Insertion (1), Suppression (1), Substitution (1)
int edit_distance(const std::string &s, const std::string &t)
{
  auto memo = std::vector<std::vector<int>>(
	s.size()+1, std::vector<int>(t.size()+1, 0));

  for(auto i = 0; i < s.size()+1; i++)
  {
    for(auto j = 0; j < t.size()+1; j++)
    {
      if(i == 0)
        memo[i][j] = j;
      else if(j == 0)
        memo[i][j] = i;
      else
      {
        auto deletion = 1 + memo[i-1][j];
        auto insertion = 1 + memo[i][j-1];
        auto substitution = memo[i-1][j-1] + ( (s[i-1] == t[j-1]) ? 0 : 1 );
        memo[i][j] = std::min(deletion, std::min(insertion, substitution));
      }
    }
  }
  return memo[s.size()][t.size()];
} // edit_distance()

int main()
{
  std::string s, t;

  std::cin >> s;
  std::cin >> t;

  printf("%d\n", edit_distance(s, t));

  return 0;
} // main()