int main(){
	string x, y;
	cin >> x >> y;

	vector<vector<int> > dp(x.size()+1, vector<int>(y.size()+1, INF));
	REP(i, x.size()) dp[i][0]=i;
	REP(i, y.size()) dp[0][i]=i;

	FOR(i, 1, x.size()+1){
		FOR(j, 1, y.size()+1){
			int tmp=dp[i-1][j-1];
			if(x[i-1]!=y[j-1]) tmp++;
			dp[i][j]=min(tmp, min(dp[i-1][j]+1, dp[i][j-1]+1));
		}
	}
	cout << dp[x.size()][y.size()] << endl;
}