/*
 * Problem     : AOJ0015
 * Title       : Integral
 * Author      : mizo0203
 * Copyright   : Your copyright free
 * Description : 文字列・多倍長演算
 */

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int N, f;
const char* str1;
const char* str2;
string str3, str4;
int sum[80];

void init() {
  scanf("%d", &N);
}

bool input() {

  if (!N)
    return false;
  N--;

  f = 0;
  cin >> str3;
  cin >> str4;
  if (str3.length() > 80 || str4.length() > 80) {
    f = 1;
    return true;
  }
  str1 = str3.c_str();
  str2 = str4.c_str();

  return true;
}

int main() {
  int i;

  init();
  while (input()) {
    if (f) {
      printf("overflow\n");
      continue;
    }
    fill(sum, sum + 80, 0);
    for (i = 0; i < (int) strlen(str1); i++) {
      sum[i] = str1[strlen(str1) - i - 1] - '0';
    }
    f = 0;
    for (i = 0; i < (int) strlen(str2); i++) {
      sum[i] += str2[strlen(str2) - i - 1] - '0' + f;
      f = 0;
      if (sum[i] > 9) {
        sum[i] -= 10;
        f = 1;
      }
    }
    for (; i < 80; i++) {
      sum[i] += f;
      f = 0;
      if (sum[i] > 9) {
        sum[i] -= 10;
        f = 1;
      }
    }
    if (f) {
      printf("overflow\n");
      continue;
    }
    for (i = 0; i < 79; i++) {
      if (sum[79 - i] != 0)
        break;
    }
    for (; i < 80; i++) {
      printf("%d", sum[79 - i]);
    }
    printf("\n");
  }

  return 0;
}