import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

import static java.lang.Math.min;

public class alg3_task_D {
    public static void main(String[] args) throws IOException{
        //Scanner sc = new Scanner(new File("input.txt"));
        //PrintWriter printWr = new PrintWriter(new File("output.txt"));
        Scanner sc = new Scanner(System.in);
        String str1 = sc.next();
        String str2 = sc.next();
        sc.close();
        int[][] dp = new int[str1.length() + 1][str2.length() + 1];
        for (int i = 1; i <= str1.length(); i++){
            dp[i][0] = dp[i - 1][0] + 1;
        }
        for (int i = 1; i <= str2.length(); i++){
            dp[0][i] = dp[0][i - 1] + 1;
        }
        for (int i = 0; i < str1.length(); i++){
            for (int j = 0; j < str2.length(); j++){
                if (str1.charAt(i) == str2.charAt(j)){
                    dp[i + 1][j + 1] = dp[i][j];
                } else {
                    int a = min( dp[i][j + 1], dp[i + 1][j]);
                    dp[i + 1][j + 1] = min(dp[i][j], a) + 1;
                }
            }
        }
        //printWr.print(dp[str1.length()][str2.length()]);
        System.out.println(dp[str1.length()][str2.length()]);
        //printWr.close();
    }
}