#include <bits/stdc++.h>
using namespace std;

void work() {
    int A, B, C, D;
    cin >> A >> B >> C >> D;
    if (A < 4) cout << "0\n";
    else {
        int ans = 4;
        for (int i = 2; i <= 10; i++) {
            for (int j = 2; j <= 10; j++) {
                int a = 4;
                int b = (i - 3 + j - 3) + 2;
                int c = (i - 3 + j - 3) + 2;
                int d = (i - 2) * (j - 2);
                assert (a + b + c + d == i * j);
                if (a <= A && b <= B && c <= C && d <= D) {
                    ans = max(ans, i * j);
                } else break;
            }
        }
        for (int ij = 10; ; ij++) {
            int i = 2, j = ij - i;
            int a = 4;
            int b = (i - 3 + j - 3) + 2;
            int c = (i - 3 + j - 3) + 2;
            int d = (i - 2) * (j - 2);
            assert (a + b + c + d == i * j);
            if (a <= A && b <= B && c <= C && d <= D) {
                int l = 2, r = ij / 2;
                while (l < r) {
                    int mid = (l + r + 1) / 2;
                    if (mid * (ij - mid) <= D) l = mid;
                    else r = mid - 1;
                }
                ans = max(ans, l * (ij - l));
            } else break;
        }
        cout << ans << '\n';
    }
}

int main() {
    int T; cin >> T;
    while (T--) work();
}