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

int makeBigInt80(char*, const char*);
int sumBigInt80(char*, const char*, const char*);

int main(void){
	int i, n;
	char buf[81], a[81], b[81];
	
	scanf("%d", &n);
	
	while(n--){
		scanf(" %s", buf);
		makeBigInt80(a, buf);
		
		scanf(" %s", buf);
		makeBigInt80(b, buf);
		
		if(sumBigInt80(buf, a, b))
			printf("overflow\n");
		else{
			for(i = 0; i < 81; i++)
				if(buf[i] != '0') break;
			
			printf("%s\n", buf + i);
		}
	}
}

int makeBigInt80(char *s, const char *t){
	int l, i;
	
	l = 80 - strlen(t);
		
	for(i = 0; i < l; i++)
		s[i] = '0';
	
	strcpy(s + l, t);
	
	return 0;
}

int sumBigInt80(char *sum, const char *a, const char *b){
	int i, n;
	int m = 0;
	
	for(i = 79; i >= 0; i--){
		n = (a[i] - '0') + (b[i] - '0') + m;
		m = n / 10;
		sum[i] = (n % 10) + '0';
	}
	
	sum[80] = '\0';
	
	return (m ? -1 : 0);
}