#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main(){
  int n;
  cin >> n;
  for(int i = 0;i < n;i++){
    string a,b,c; char tmp;
    cin >> a >> b;
    if(a.size() > 80 || b.size() > 80){
      cout << "overflow" << endl;
      continue;
    }
    if(a.size() < b.size()){swap(a,b);}
    for(int k = 0;k< a.size();k++)
      c[k] = '0';
     for(int k = 0;k < b.size();k++){
       c[k] = b[b.size()-1-k];
     }
     b.resize(a.size());
     for(int k = 0;k < a.size();k++)
       {b[k] = c[k]; c[k] = a[k];} 
     for(int k = 0;k < a.size();k++){
      	a[a.size()-k-1] = c[k];
     }
	
     tmp = '0';
     for(int k = 0;k < a.size();k++){
       c[k] = a[k] + b[k] + tmp -'0' -'0';
	  if(c[k] > '9'){ tmp = '1'; c[k] = c[k] - ':' + '0'; }
	  else {tmp = '0';}
     } 
     if(a.size() <= 79 ){if(tmp == '1'){ cout << tmp;}
       for(int k = a.size()-1;k >=0;k--){
	 cout << c[k]; 
	  }
       cout << endl;
     } else {cout <<"overflow"<<endl; } 
     
  }
}