#include "bits/stdc++.h"

#define REP(i,num) for(int i=0;i<(num);++i)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto& x:c){cout<<x<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=int>
T in(){T x; cin >> x; return (x);}
template<typename T=int,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int N=in();
	REP(i,N){
		string S=in<string>();
		reverse(ALL(S));
		string T=in<string>();
		reverse(ALL(T));
		int SN=S.size(),TN=T.size();
		if(SN>TN){
			REP(j,SN-TN) T.push_back('0');
		}
		else{
			REP(j,TN-SN) S.push_back('0');
		}
		SN=S.size();
		if(SN>80){
			out("overflow");
			continue;
		}
		bool flag = SN==80?true:false,overflow=false;
		string R(SN+1,'0');
		REP(j,SN){
			int v=(S[j]-'0')+(T[j]-'0')+(R[j]-'0');
			if(v>9){
				if(j==SN-1 && flag){
					overflow = true;
					break;
				}
				R[j+1] = '1';
				R[j] = (v-10)+'0';
			}
			else R[j] = v+'0';
		}
		if(overflow){
			out("overflow");
		}
		else{
			reverse(ALL(R));
			auto itr=find_if(ALL(R),[](char ch){return ch!='0';});
			if(itr==R.end()) --itr;
			while(itr!=R.end()){
				cout << *itr;
				++itr;
			}
			cout << endl;
		}
	}

	return 0;
}
