#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int n;
	cin >> n;
	
	while(n-- > 0){
	
	string str1;
	cin >> str1;
	
	string str2;
	cin >> str2;
	
	reverse(str1.begin(), str1.end());
	reverse(str2.begin(), str2.end());
	
	int check;
	if(str1.size() > str2.size()){
		check = 1;
	}
	else if(str1.size() == str2.size()){
		check = 2;
	}
	else {
		check = 3;
	}
	
	int ans[100];
	bool next = false;
	int short_ = min(str1.size(), str2.size());
	int long_ = max(str1.size(), str2.size());	
	if(long_ >= 79){
		cout << "overflow" << endl;
		continue;
	}

	for(int i = 0; i < short_; ++i){
		int num = 0;
		num += (str1[i] - '0') + (str2[i] - '0');
		if(next){
			num++;
		}
		ans[i] = num;
		next = false;	
		if(num >= 10){
			num -= 10;
			ans[i] -= 10;
			next = true;
		}
		//cout << num << endl;
	}
	/*for(int i = 0; i < min(str1.size(), str2.size()); ++i){
		cout << ans[i];
	}
	cout << endl;*/
	
	if(check == 1){
		for(int i = str2.size(); i < str1.size(); ++i){
			int num = str1[i] - '0';
			if(next){
				num++;
			}
			ans[i] = num;
			next = false;	
			if(num >= 10){
				num -= 10;
				ans[i] -= 10;
				next = true;
			}
		}
		if(next){
			ans[str1.size()] = 1;
			long_ ++;
		}
	}	
	
	if(check == 3){
		for(int i = str1.size(); i < str2.size(); ++i){
			int num = str2[i] - '0';
			if(next){
				num++;
			}
			ans[i] = num;
			next = false;	
			if(num >= 10){
				num -= 10;
				ans[i] -= 10;
				next = true;
			}
		}
		if(next){
			ans[str2.size()] = 1;
			long_ ++;
		}
	}
	
	if(long_ >= 80){
		cout << "overflow" << endl;
		continue;
	}

	for(int i = long_ - 1; i >= 0; --i){
		cout << ans[i];
	}/*
	for(int i = 0; i < min(str1.size(), str2.size()) + 1; ++i){
		cout << ans[i];
	}*/

	cout << endl;
	//reverse(ans.begin(), ans.end());
	//cout << ans << endl;
	}
		
	return 0;
}