#include <iostream>
#include <algorithm>
using namespace std;
const int N = 1010;
int n, m;
char a[N], b[N];
int f[N][N];//a的前N个去匹配b的前N个需要编辑的最小操作
int main() {
scanf("%d%s", &n, a + 1);
scanf("%d%s", &m, b + 1);
for (int i = 0; i <= m; i ++ ) f[0][i] = i;//a的前0个字母去匹配b的前i个字母,只能加
for (int i = 0; i <= n; i ++ ) f[i][0] = i;//a的前i个字母去匹配b的前0个字母,只能减
for (int i = 1; i <= n; i ++ )
for (int j = 1; j <= m; j ++ ) {
// 删除操作 增
f[i][j] = min(f[i - 1][j] + 1, f[i][j - 1] + 1);
// 改
if (a[i] == b[j]) f[i][j] = min(f[i][j], f[i - 1][j - 1]);
else f[i][j] = min(f[i][j], f[i - 1][j - 1] + 1);
}
printf("%d
", f[n][m]);
return 0;
}