import std.stdio, std.bigint, std.conv, std.string;

void main(){
    int n = readln.chomp.to!int;
    foreach(i; 0..n){
        auto a = readln.chomp;
        auto b = readln.chomp;
        if(a.length > 80 || b.length > 80){
            "overflow".writeln;
            continue;
        }
        auto res = (a.BigInt + b.BigInt).to!string;
        if(res.length > 80)
            "overflow".writeln;
        else
            res.writeln;
    }
}