#include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int main() {
	int n;
	cin >> n;

	for (int i = 0; i < n; i++) {
		string num1, num2;
		cin >> num1 >> num2;
		if (num1.size() < num2.size()) swap(num1, num2);
		if (num1.size() > 80) {
			cout << "overflow\n";
			continue;
		}

		reverse(num1.begin(), num1.end());
		reverse(num2.begin(), num2.end());

		for (int j = 0; j < num2.size(); j++) {
			int p = (num1[j] - '0') + (num2[j] - '0');
			if (p >= 10) {
				num1[j] = ((num1[j] - '0') + (num2[j] - '0')) % 10 + '0';

				int k = j + 1;
				while (num1[k] == '9' && k < num1.size()) {
					num1[k++] = '0';
				}
				
				if (k == num1.size()) num1 = num1 + "1";
				else num1[k]  = num1[k] + 1;
			}
			else {
				num1[j] = num1[j] + (num2[j] - '0');
			}
		}
		if (num1.size() > 80) {
			cout << "overflow\n";
			continue;
		}
		reverse(num1.begin(), num1.end());
		cout << num1 << endl;
	}
}
