#include<iostream>
#include<stdio.h>
#include<string.h>

int n;
char a[1000];
int temp[1000], temp2[1000], temp3[1000];

int main()
{
        std::cin >> n;
	
	while( n-- ){
		memset( temp, -1, sizeof( temp ) );
		memset( temp2, -1, sizeof( temp2 ) );
		memset( temp3, 0, sizeof( temp3 ) );
		
		std::cin >> a;
		
		for( int i = 0; i < strlen( a ); i++ ){
			temp[strlen( a ) - i - 1] = a[i] - '0';
		}
		
		std::cin >> a;
		
		for( int i = 0; i < strlen( a ); i++ ){
			temp2[strlen( a ) - i - 1] = a[i] - '0';
		}
		
		int p = 0, f = 0;
		while( 1 ){
		 	if( temp[p] != -1 && temp2[p] != -1 ){
			 	temp3[p] = ( temp[p] + temp2[p] + f ) % 10;
				f = ( temp[p] + temp2[p] + f ) / 10;
			}
			else if( temp[p] != -1 ){
				temp3[p] = ( temp[p] + f ) % 10;
				f = ( temp[p] + f ) / 10;
			}
			else if( temp2[p] != -1 ){
				temp3[p] = ( temp2[p] + f ) % 10;
				f = ( temp2[p] + f ) / 10;
			}
			else break;
			
			p++;
		}
		
		if( p + f > 79 ){
			std::cout << "overflow" << std::endl;
			continue;
		}
		
		if( f )std::cout << -temp[p];
		
		for( int i = p - 1; i >= 0; i-- ){
		 	std::cout << temp3[i];
		}
		std::cout << std::endl;
	}

 	return 0;
}