#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <string>
#include <algorithm>
#include <string>
#include <climits>

#define REP(i, n) for (int (i) = 0; (i) < (int)(n); (i)++)
#define REG(i, a, b) for (int (i) = ((int)(a)); (i) < ((int)(b)); i++)
#define ALL(V) (V).begin(), (V).end()
#define PRINT(STR) cout << (STR) << endl

typedef long long ll;
using namespace std;

double nextDouble() {
	double d = -1;
	cin >> d;
	return d;
}

int nextInt() {
	int n = -1;
	cin >> n;
	return n;
}

string nextString() {
	string str;
	cin >> str;
	return str;
}

string reverse(string str) {
	string t = str;
	for (int i = 0; i < str.size(); i++) {
		t[i] = str[str.size() - i - 1];
	}
	return t;
}

int main() {
	cin.tie(0); //対話型には使えない
	int n = nextInt();
	while (n--) {
		string str1 = nextString();
		if (str1.size() > 80) {
			cout << "overflow" << endl;
			continue;
		}
		string str2 = nextString();
		if (str2.size() > 80) {
			cout << "overflow" << endl;
			continue;
		}
		str1 = reverse(str1);
		str2 = reverse(str2);
		char ans[82];
		int m = max(str1.size(), str2.size());
		int k = 0;
		int i;
		for (i = 0; i < m; i++) {
			int t = 0;
			if (i < str1.size()) {
				t += str1[i] - '0';
			}
			if (i < str2.size()) {
				t += str2[i] - '0';
			}
			t += k;
			ans[i] = (t % 10) + '0';
			k = t / 10;
		}
		if (k != 0) {
			if (i > 80) {
				cout << "overflow" << endl;
				continue;
			}
			ans[i] = k + '0';
			ans[i + 1] = '\0';
		} else {
			ans[i] = '\0';
		}
		cout << reverse(ans) << endl;
	}
	return 0;
}