#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,a) FOR(i,0,a)

vector<int> a(200);
vector<int> b(200);
vector<int> comp(200);

void dfs(int i){
	//i?????????1?¶????
	if (comp[i]<9){
		comp[i]++;
	}
	else{
		comp[i]=0;
		dfs(i+1);
	}
}

int main(){
	int N;
	cin>>N;
	REP(i,N){
		string s1,s2;
		REP(j,200){
			comp[j]=b[j]=0;
		}
		cin>>s1;
		cin>>s2;
		REP(j,s1.size()){
			comp[j]=s1[s1.size()-j-1]-'0';
		}
		REP(j,s2.size()){
			b[j]=s2[s2.size()-j-1]-'0';
		}
		REP(j,s2.size()){
			comp[j]+=b[j];
			if (comp[j]>9){
				comp[j]-=10;
				dfs(j+1);
			}
		}
		int fl=200-1;
		while(!comp[fl]) fl--;
		fl++;
		if (fl>80){
			cout<<"overflow"<<endl;
		}
		else{
			for(int k=fl-1;k>=0;k--){
				cout<<comp[k];
			}
			cout<<endl;
		}
	}
	return 0;
}