else怎么写？

#include <bits/stdc++.h>
using namespace std;
int k;
long long n, e, d, p, q, b, c, dt;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> k;
    for (int i = 1; i <= k; i++) {
        cin >> n >> e >> d;
        b = e * d - n - 2, c = n;
        dt = b * b - 4 * c;
        int y = round(sqrt(dt));
        if (dt < 0) {
            cout << "NO\n";
        } else if (y * y != dt) {
            cout << "NO\n";
        } else {
            cout<<?;
        }
    }
    return 0;
}