#define scanf_s scanf
#define sscanf_s sscanf
#include <string>
#include <iostream>
#include <math.h>
using namespace std;
#define MAX 81
#define _MAX 100
//#define CONSTNUM 10000000
int main(void)
{
	int n, s = 0, x, y, r = 0, a, b;
	int sum_n[50][3] = { 0 };
	char sum[50][_MAX], astr[_MAX], bstr[_MAX], num[11] = { "0123456789" };
	char ca, cb;
	scanf_s("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf_s("%s %s", &astr, &bstr);
		for (x = 0; astr[x] != '\0'; ++x);
		for (y = 0; bstr[y] != '\0'; ++y);
		if (x > 80 || y > 80) {
			printf("overflow\n");
			continue;
		}
		for (int j = 0; j < x || j < y; ++j) {
			if (j < x && j < y) {
				ca = astr[x - j - 1]; cb = bstr[y - j - 1];
				sscanf_s(&ca, "%d", &a);
				sscanf_s(&cb, "%d", &b);
				if (x > y) sum[i][x - j] = num[(a + b + r) % 10];
				else sum[i][y - j] = num[(a + b + r) % 10];
				if (a + b + r >= 10) r = (a + b + r) / 10;
				else r = 0;
			}
			else {
				if (x > y) {
					if (r != 0) {
						ca = astr[x - j - 1];
						sscanf_s(&ca, "%d", &a);
						sum[i][x - j] = num[(a + r) % 10];
						if (a + r >= 10) r = (a + r) / 10;
						else r = 0;
					}
					else {
						sum[i][x - j] = astr[x - j - 1];
					}
				}
				else {
					if (r != 0) {
						cb = bstr[y - j - 1];
						sscanf_s(&cb, "%d", &b);
						sum[i][y - j] = num[(b + r) % 10];
						if (b + r >= 10) r = (b + r) / 10;
						else r = 0;
					}
					else {
						sum[i][y - j] = astr[y - j - 1];
					}
				}
			}
		}
		sum_n[i][0] = x; sum_n[i][1] = y; sum_n[i][2] = r;
		r = 0;
	}
	for (int i = 0; i < n; ++i) {
		x = sum_n[i][0]; y = sum_n[i][1]; r = sum_n[i][2];
		if (y <= 80 - r && x <= 80 - r) {
			if (r == 1) printf("%d", r);
			for (int j = 1; j <= x || j <= y; ++j) {
				printf("%c", sum[i][j]);
			}
		}
		else {
			printf("overflow");
		}
		printf("\n");
	}
}