#include <cstdio>
using namespace std;

int main(){
	int N;
	char str1[90], str2[90];
	int num1[80], num2[80], sum[80];
	int pos, pos2, up;
	
	scanf("%d", &N);
	for(int n = 0; n < N; n++){
		for(int i = 0; i < 90; i++){
			str1[i] = 0;
			str2[i] = 0;
		}
		for(int i = 0; i < 80; i++){
			num1[i] = 0;
			num2[i] = 0;
			sum[i] = 0;
		}
		scanf("%s", str1);
		scanf("%s", str2);
		
		pos = 89;
		while(pos >= 0 && str1[pos] == 0) pos--;
		pos2 = 0;
		while(pos >= 0 && pos2 < 80 && str1[pos] != 0){
			num1[pos2] = str1[pos] - 48;
			pos2++; pos--;
		}
		pos = 89;
		while(pos >= 0 && str2[pos] == 0) pos--;
		pos2 = 0;
		while(pos >= 0 && pos2 < 80 && str2[pos] != 0){
			num2[pos2] = str2[pos] - 48;
			pos2++; pos--;
		}
		
		/*for(int i = 0; i < 80; i++) printf("%d", num1[i]);
		printf("\n");
		for(int i = 0; i < 80; i++) printf("%d", num2[i]);
		printf("\n");*/
		
		up = 0;
		for(int i = 0; i < 80; i++){
			sum[i] = num1[i] + num2[i] + up;
			up = sum[i] / 10;
			sum[i] = sum[i] % 10;
		}
		
		if(up > 0 || sum[79] > 0 || num1[79] > 0 || num2[79] > 0) printf("overflow\n");
		else{
			pos = 79;
			while(pos >= 0 && sum[pos] == 0) pos--;
			if(pos < 0) printf("0");
			while(pos >= 0){
				printf("%d", sum[pos]);
				pos--;
			}
			printf("\n");
		}
	}
	
	return 0;
}