import java.util.*;

class Main {

    public static int editDist(String str, String target) {
        int n = str.length(), m = target.length();
        int[][] dp = new int[n + 1][m + 1];
        for (int i = 0; i <= m; i++)
            dp[0][i] = i;
        for (int i = 0; i <= n; i++)
            dp[i][0] = i;

        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++) {
                char ct = target.charAt(i);
                char cs = str.charAt(j);
                dp[j + 1][i + 1] = dp[j][i + 1] + 1; // Delete
                dp[j + 1][i + 1] = Math.min(dp[j + 1][i + 1], dp[j + 1][i] + 1); // insert
                dp[j + 1][i + 1] = Math.min(dp[j + 1][i + 1], dp[j][i] + 1); // replace
                if (ct == cs)
                    dp[j + 1][i + 1] = Math.min(dp[j + 1][i + 1], dp[j][i]); // equals
            }
        return dp[n][m];
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String strN = sc.next();
        int m = sc.nextInt();
        String strM = sc.next();
        System.out.println(editDist(strN, strM));
        return;
    }

}