#include <bits/stdc++.h>

using namespace std;

#define endl '\n'

void solve(){
	int l1, r1, l2, r2;
	cin >> l1 >> r1 >> l2 >> r2;
	int x = l1 + l2;
	
	int add = (r1 - l1) + r2 - l2;
	
	int ans = 0;
	int X = x;
	while (X){
		ans = max(ans, X % 10);
		X /= 10;
	}
	
	if (add >= 9) {cout << 9 << endl; return ;}
	
	ans = max(add, ans);
	
	int y = x % 10, z = x % 100;
	if (add + y > 9){
		ans = 9;
	}else{
		ans = max(ans, y + add);
	}
	
	
	cout << ans << endl;
	
	
}


int main(){
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	
	int t = 1;
	cin >> t;
	while (t --) solve();
}