
#include <cmath>
#include <iostream>
#include <cstdio>
#include <ctype.h>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <iomanip>
#include <set>
#include <stack>
#include <queue>
#include <vector>
#include <sstream>


using namespace std;


string reverse(string str)
{
	string ret = "";
	
	for (int i=str.length()-1; i>=0; i--)
	{
		ret += str[i];
	}
	
	return ret;
}


/*
指定したインデックスの文字を数値に直して返す関数。
インデックスが不正な場合は数値0を返す。
*/
int new_at(string str, int index)
{
	stringstream ss;
	int ret;
	
	if (index >= str.length())
	{
		return 0;
	} else {
		ss << str[index];
		ss >> ret;
		
		return ret;
	}
}


int main()
{
	int n;
	int ia, ib;
	int flag = 0;	//繰り上がりのフラグ(繰り上がる場合は1)
	int num = 0;	//各桁の和
	
	string sa, sb;	//入力値
	string ra, rb;	//反転した入力値
	
	string sum = "";
	stringstream ss;
	int cnt;	//長いほうの文字数
	
	
	cin >> n;
	for (int i=0; i<n; i++)
	{
		cin >> sa >> sb;
		ra = reverse(sa);
		rb = reverse(sb);
		//cout << "ra = " << ra << " : rb = " << rb << endl;
		
		cnt = (ra.length() > rb.length()) ? ra.length() : sb.length();
		//cout << "cnt = " << cnt << endl;
		
		for (int j=0; j<cnt; j++)
		{
			num += new_at(ra, j) + new_at(rb, j);
			if (flag) num++;
			//cout << "(j=" << j << ") : num = " << num << endl;
			
			if (num >= 10)
			{
				num = num - 10;
				ss << num;
				sum += ss.str();
				num = 0;
				flag = 1;
			} else {
				ss << num;
				sum += ss.str();
				num = 0;
				flag = 0;
			}
			
			ss.str("");
			
			//cout << "(j=" << j << ") : sum = " << sum << endl;
		}
		
		if (flag)
		{
			sum += "1";
			flag = 0;
		}
		
		if (sum.length() > 80)
		{
			cout << "overflow" << endl;
		} else {
			//cout << "sum = " << reverse(sum) << endl;
			cout << reverse(sum) << endl;
		}
		
		sum = "";
		num = 0;
		//cout << "new_at = " << new_at(sa, 3) << endl;
		//cout << "sa = " << reverse(sa) << " : sb = " << reverse(sb) << endl;
		//cout << "sa[0] = " << sa[0] << " : sb[0] = " << sb[0] << endl;
	}
	
	return 0;
}