#include <string>
#include <vector>
#include <iostream>

#define debug(x) cout<<#x<<": "<<x<<endl
#define rep(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for (int i=(a);i<=(b);i++)
#define all(a) (a).begin(),(a).end()
using namespace std;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef long long ll;

void solve() {
	int n;
	cin >> n;
	rep(i, n) {
		vector<ll> v1(11), v2(11);
		string s1, s2;
		cin >> s1 >> s2;
		rep(j, 10) {
			if (s1.size() > 10 * j) v1[j] = stoi(s1.substr(10 * j, (s1.size() - 10 * j >= 10 ? 10 : s1.size() - 10 * j)));
			if (s2.size() > 10 * j) v2[j] = stoi(s2.substr(10 * j, (s2.size() - 10 * j >= 10 ? 10 : s2.size() - 10 * j)));
		}
		rep(j, 11) {
			v1[j] += v2[j];
			if (v1[j] >= 1e10) {
				v1[j] -= 1e10;
				v2[j]++;
			}
		}
		if (v1[8] || v1[9] || v1[10]) cout << "overflow" << endl;
		else {
			rep(j, 11) if (v1[10 - j] != 0) cout << v1[10 - j];
			cout << endl;
		}
	}

}




int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	solve();
	//system("PAUSE");
	return 0;
}