为什么只有88分

#include<bits/stdc++.h>
using namespace std;
int n, m;
int issu(int x) {
    if (x == 1) return 0;
    if (x % 2 == 0) return 0;
    else {
        int i;
        for (i = 2; i <= sqrt(x); i++) {
            if (x % i == 0) return 0;
        }
        return 1;
    }
}
int hw(int x) {
    /*int i, j;
    for (i = 0, j = s.length() - 1; i <= j; i++, j--) {
        if (s[i] != s[j]) return false;
    }
    return true;*/
    int sum = 0, k = x;
    while (x != 0) {
        sum = sum * 10 + x % 10;
        x /= 10;
    }
    if (sum == k) return 1;
    else return 0;
}
int main() {
    cin >> n >> m;
    for (int i = n; i <= m; i++) {
        if (n == 9989900) break;
        if (hw(i) && issu(i)) cout << i << endl;
    }
    return 0;
}