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

int main(){
	int i,j,k,n,tmp,flag,length;
	int yosan[20];
	char str[81],str2[256];

	scanf("%d",&n);

	for(i = 0;i < n;i++){
		memset(yosan,0,sizeof(yosan));
		flag = 0;
		for(j = 0;j < 2;j++){
			scanf("%s",str2);
			length = strlen(str2);
			if(flag && length >= 81){
				flag = 1;
				break;
			}
			memset(str,'\0',sizeof(str));
			for(k = 0;k < 80;k++){
				if(k >= 80-length){
					str[k] = str2[k-80+length];
				}else{
					str[k] = '0';
				}
			}
			//printf("%s\n",str);
			tmp = 0;
			for(k = 0;k < 80;k++){
				tmp *= 10;
				tmp += (str[k] - '0');
				if(k % 4 == 3){
					yosan[k/4] += tmp;
					tmp = 0;
				}
			}
			for(k = 29;k > 0;k--){
				if(yosan[k] >= 10000){
					yosan[k-1]++;
					yosan[k] %= 10000;
				}
			}
			if(yosan[0] >= 10000){
				flag = 1;
				break;
			}
		}
		if(!flag){
			tmp = 0;
			while(yosan[tmp] == 0){
				tmp++;
			}
			printf("%d",yosan[tmp]);
			tmp++;
			for(j = tmp;j < 20;j++){
				printf("%04d",yosan[j]);
			}
			printf("\n");
		}else{
			printf("overflow\n");
		}
	}

	return 0;
}