#include<iostream>
#include<string>
#include<math.h>
using namespace std;
int main() {
	int N,a,b,c,d,f;
	int e = 0;
	string s,t,u;
	cin >> N;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < 2; j++) {
			if (j == 0) {
				cin >> s;
			}
			else if (j == 1) {
				cin >> t;
			}
		}
		a = s.size();
		b = t.size();
		if (a < b) {
			c = a;
		}
		else if (a >= b) {
			c = b;
		}
		for (int k =c; k >= 0; k++) {
			d = s[c - 1] + t[c - 1];
			while (e == 1) {
				e = 0;
				d += 1;
			}
			if (d < 10) {
				u[c - k] = d;
			}
			else {
				u[c - k] = d - 10;
				e = 1;
			}
		}
		f = u.size();
		while (f > 80) {
			cout << "overflow" << endl;
			break;
		}
		while (f <= 80) {
			for (int i2 = 0; i2 < f; i2++) {
				cout<< u[f - 1 - i2];
			}
			break;
		}
	}
	return 0;
}