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

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

  while (N--) {
    int num_size;
    string num1, num2;
    cin >> num1 >> num2;

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

    num_size = max(num1.size(), num2.size());
    if (num_size > 80) {
      cout << "overflow" << endl;
      continue;
    }
    if (num1.size() > num2.size()) {
      int diff = num1.size() - num2.size();
      while (diff--) {
        num2 += '0';
      }
    } else {
      int diff = num2.size() - num1.size();
      while (diff--) {
        num1 += '0';
      }
    }

    string sum;
    bool flag = false;
    for (int i = 0; i < num_size; i++) {
      int n1 = num1[i] - '0';
      int n2 = num2[i] - '0';
      int tmp = n1 + n2;
      if (flag) {
        tmp++;
        flag = false;
      }
      if (tmp >= 10) {
        tmp %= 10;
        flag = true;
      }
      sum += tmp + '0';
    }

    if (sum.size() > 80) {
      cout << "overflow" << endl;
      continue;
    }
    
    reverse(sum.begin(), sum.end());
    cout << sum << endl;

  }

  return 0;
}