#include<iostream>
#include<string>
#include<math.h>
using namespace std;
int main() {
	int N,a,b,c,d,f;
	int e = 0;
	int g = 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;
			g = b - a;
		}
		else if (a > b) {
			c = b;
			g = a - b;
		}
		else if (a == b) {
			c = a;
			g = 0;
		}
		for (int k = c - 1; k >= 0; k--) {
			d = s[k] + t[k];
				u[c - k - 1] = d;
		}
		while (g == b - a) {
			for (int i3 = c; i3 < b; i3++) {
				u[i3] = t[i3];
			}
			break;
		}
		while (g == a - b) {
			for (int i4 = c; i4 < a; i4++) {
				u[i4] = s[i4];
			}
			break;
		}
		f = u.size();
		for (int i5 = 0; i5 < f-1; i5++) {
			if (u[i5] > 10) {
				u[i5+1] += 1;
				u[i5] -= 10;
			}
		}
		while (u[f - 1] > 10) {
			u[f] = 0;
			break;
		}
		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;
}