#include <bits/stdc++.h>
using namespace std;

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

	string A, B;
	for (int i = 0; i < N; i++) {
		cin >> A >> B;
		int nl, ml;
		nl = A.size();
		ml = B.size();
		string a, b;
		if (nl >= ml) {
			a = A;
			b = B;
		}
		else {
			a = B;
			b = A;
		}
		//cout << "a:" << a << ' ' << "b:" << b << endl;

		int f = 0, of = 0;
		int as = a.size(),
			bs = b.size();
		int AL = as;
		as--;
		bs--;
		while (1) {
			int n = (int)a.at(as) - '0',
				m = (int)b.at(bs) - '0';
			as--;
			bs--;
			//cout << n << ' ' << m << endl;

			int r = n + m;
			if (f) {
				r++;
				f = 0;
			}
			a.at(as + 1) = (char)r%10 + 48;

			if (r > 9) {
				f = 1;

				if (as < 0 && bs < 0) {
					of = 1;
					AL++;
					break;
				}
				else if (as >= 0 && bs < 0) {
					for (int j = as; j >= 0; j--) {
						int n2 = (int)a.at(j) - '0';
						if (f) {
							n2++;
							f = 0;
						}
						a.at(j) = (char)n2 % 10 + 48;
						
						if (n2 > 9) {
							f = 1;
							if (!j) {
								of = 1;
								AL++;
								break;
							}
						}
					}
				}
			}

			if (bs < 0) break;
		}

		if (AL > 80) {
			cout << "overflow" << endl;
		}
		else {
			if (of) cout << 1;
			cout << a << endl;
		}
	}
}
