#include <algorithm>
#include <cstdio>
#include <vector>

constexpr int MAX_N = 1001;
constexpr int MAX_M = 1001;

// 斜向箭头：匹配成功时，操作总数不变；匹配失败时，操作总数加一。
// 横向箭头、竖向箭头：操作总数加一。

int main()
{
    char s_a[MAX_N] = { 0 };
    char s_b[MAX_M] = { 0 };
    int N, M;
    scanf("%d", &N);
    scanf("%s", s_a);
    scanf("%d", &M);
    scanf("%s", s_b);
    std::vector<std::vector<int>> num_op(N + 1, std::vector<int>(M + 1));

    for(int i = 0; i <= N; ++i){
        num_op[i][0] = i;
    }
    for(int j = 0; j <= M; ++j){
        num_op[0][j] = j;
    }

    for (int i = 0; i < N; ++i) {
        for (int j = 0; j < M; ++j) {
            num_op[i + 1][j + 1] = std::min(num_op[i + 1][j] + 1,
                num_op[i][j + 1] + 1);
            num_op[i + 1][j + 1] = std::min(num_op[i + 1][j + 1], 
                num_op[i][j] + (s_a[i] != s_b[j]));
        }
    }

    printf("%d\n", num_op[N][M]);

    return 0;
}