// Advanced Algorithms - Chapter 14.
// Coût minimal de transformation d'une chaîne en une autre.
#include <iostream>
#include <vector>
#include <limits>
#include <algorithm>
using namespace std;

// Distance de Levenshtein
// Insertion (1), Suppression (1), Substitution (1)
int edit_distance(const string &s, const string &t)
{
	// matrice de mémoïzation : "distance" entre s[0 .. i] et t[0 .. j]
	auto memo = vector<vector<int>>(s.size() + 1, vector<int>(t.size() + 1, 0));

	for(size_t i = 0; i < s.size()+1; i++)
	{
		for(size_t j = 0; j < t.size()+1; j++)
		{
			if(i == 0)
				memo[i][j] = j;
			else if(j == 0)
				memo[i][j] = i;
			else
			{
				auto insertion = 1 + memo[i][j-1];

				auto deletion = 1 + memo[i-1][j];

				auto substitution = memo[i-1][j-1] +
					( (s[i-1] == t[j-1]) ? 0 : 1 );

				memo[i][j] = min(deletion, min(insertion, substitution));
			}
		}
	}
	return memo[s.size()][t.size()];
} // edit_distance()

int main()
{
	string s, t;
	cin >> s >> t;

	cout << edit_distance(s, t) << '\n';

	return 0;
} // main()