#include<iostream>
using namespace std;

const int N = 1010;
char a[N], b[N];
int n, m;
int f[N][N];

int main(){
    scanf("%d%s%d%s", &n, a + 1, &m, b + 1);
    
    for(int i = 0; i <= m; i ++) f[0][i] = i;
    for(int i = 0; i <= n; i ++) f[i][0] = i;
    
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++){
            f[i][j] = min(f[i - 1][j], f[i][j - 1]) + 1;
            f[i][j] = min(f[i][j], f[i - 1][j - 1] + (a[i] != b[j]));
        }
        
    cout << f[n][m];
}