C

#include <stdio.h>

#define MAXSIZE 1010
#define min(a,b) ((a)<(b)?(a):(b))
int n, m, dp[MAXSIZE][MAXSIZE];
char a[MAXSIZE], b[MAXSIZE];

int main() {
    scanf("%d%s%d%s", &n, a+1, &m, b+1);
    for (int i = 1; i < MAXSIZE; ++i) {
        dp[i][0] = dp[0][i] = i;
    }

    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            dp[i][j] = min(dp[i-1][j], dp[i][j-1]) + 1;
            if (a[i] == b[j]) {
                dp[i][j] = min(dp[i][j], dp[i-1][j-1]);
            } else {
                dp[i][j] = min(dp[i][j], dp[i-1][j-1]+1);
            }
        }
    }
    printf("%d\n", dp[n][m]);

    return 0;
}