import std.stdio, std.conv, std.string, std.range, std.array, std.algorithm;
import std.bigint;

void main()
{
  int n = readln().chomp().to!int;

  while (n--){
    BigInt a = readln().chomp().to!BigInt;
    BigInt b = readln().chomp().to!BigInt;
    if ((a + b).to!string.length > 80){
      writeln("overflow");
    } else {
      writeln(a + b);
    }
  }
}