求助！！第11个点WA了

感觉没啥错。。

#include<iostream>
#include<algorithm>
#define int long long
using namespace std;
int n, m, ans = 0;
int mon1[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int mon2[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int check1(int x)
{
    int a, b, c, d, e;
    e = x % 10000;
    a = e % 10;
    b = e % 100 / 10;
    c = e / 100 % 10;
    d = e / 1000;
    //cout << a << " " << b << " " << c << " " << d << endl;
    //cout << x / 10000 << " " << a * 1000 + b * 100 + c * 10 + d << endl;
    if (x / 10000 == a * 1000 + b * 100 + c * 10 + d) return true;
    else return false;
}
int check2(int x)
{
    int nian, f = 0;
    nian = x / 10000;
    if (nian % 400 == 0 || (nian % 4 == 0 && nian % 100)) f = 1;
    int t, h;
    t = x % 10000 / 100;
    //cout << t << " ";
    h = x % 10000 % 100;
    //cout << h << " ";
    if (f == 1) 
    {
        if (t > 12 || t < 1) return false;
        else if (mon1[t] < h) return false;
    }
    else {
        if (t > 12 || t < 1) return false;
        else if (mon2[t] < h) return false;
    }
    return true;
}
signed main()
{
    cin >> n >> m;
    for (int i = n;i <= m;i += 10000)
    {
        int k;
        k = i / 10000;
        int a, b, c, d;
        a = k % 10;
        b = k % 100 / 10;
        c = k / 100 % 10;
        d = k / 1000;
        int z;
        z = k * 10000 + a * 1000 + b * 100 + c * 10 + d;
        if (check2(z)) ans ++;
    }
    cout << ans << endl;
    return 0;
}