//http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0015&lang=jp
#include <iostream>
#include <cstdio>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <array>
#include <numeric>
#include <functional>

#define rep(i,n) for(int i=0;i<n;i++)
#define scanInt(i) scanf("%d", &i)

using namespace std;

int main(){

	int n;
	scanInt(n);
	rep(i,n){
        string str1, str2;
        cin >> str1 >> str2;
        if(str1.size() > 80 || str2.size() > 80){
            printf("overflow\n");
        }
        else{
            unsigned long long a = std::stoull(str1);
            unsigned long long b = std::stoull(str2);
            printf("%llu\n", a+b);
        }
    }

    return 0;
}