//#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "bits/stdc++.h"

#define rep(i,n) for(ll (i)=0;(i)<(ll)(n);(i)++)
#define all(x) (x).begin(),(x).end()

#define MOD 1000000007LL
#define INF (1LL<<60LL)
#define int long long
#define MAX_N (100001)
typedef long long ll;

using namespace std;

string stringsum(string s1, string s2) {
	if (s1 == s2 && s1 == "0") return "0";
	string s;
	reverse(all(s1));
	reverse(all(s2));
	int len1 = s1.size();
	int len2 = s2.size();
	bool up = false;
	for(int i=0;i<=100;i++) {
		//cout << i << endl;
		if (len1 <= i && len2 <= i)break;
		int k = 0;
		if (up) {
			k++;
			up = false;
		}
		string c;
		if (len1>i){
			c = s1[i];
			k += stoi(c);
		}
		if (len2 > i) {
			c = s2[i];
			k += stoi(c);
		}
		if (k >= 10) {
			up = true;
			k -= 10;
		}
		s += to_string(k);
		//cout << k << " ";
		//cout << s << endl;
	}
	if (up)s += '1';
	reverse(all(s));
	return s;
}


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n; cin >> n;
	rep(i, n) {
		string s1, s2;
		cin >> s1 >> s2;
		string s;
		s = stringsum(s1, s2);
		if (s.size() > 80) cout << "overflow" << endl;
		else cout << s << endl;
	}
}

