#include <bits/stdc++.h>

using namespace std;

int main() {
    int t, al, ar, bl, br;
    scanf("%d", &t);
    while (t--) {
        scanf("%d%d%d%d", &al, &ar, &bl, &br);
        int l = al + bl, r = ar + br;
        // the max digit of any integer between l and r
        if (l / 10 != r / 10) {
            printf("9\n");
        } else {
            int ans = 0;
            while (l) {
                ans = max(ans, l % 10);
                l /= 10;
            }
            while (r) {
                ans = max(ans, r % 10);
                r /= 10;
            }
            printf("%d\n", ans);
        }
    }
}