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

int main(){

  int n;
  string s,t;

  cin >> n;
  for(;n>0;n--){
    cin >> s >> t;

    reverse(s.begin(),s.end());
    reverse(t.begin(),t.end());

    int ns = s.size(), nt = t.size();
    int nn = max(ns,nt);

    for(int i=ns;i<nn;i++) s += '0';
    for(int i=nt;i<nn;i++) t += '0';

    int c = 0;
    string ss = "";
    
    for(int i=0;i<nn;i++){
      int k = c + s[i] + t[i] - '0';

      if(k <= '9') ss += k, c = 0;
      if(k > '9') ss += k - 10, c = 1;

    }

    if(c == 1) ss += '1';

    reverse(ss.begin(),ss.end());
    if(ss.size() > 80) cout << "overflow" << endl;
    else cout << ss << endl;

  }
}