#include<stdio.h>
#include<iostream>
#include<list>
#include<map>
#include<vector>
#include<algorithm>
#include<string.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define debug(x) cout << x << endl;
using namespace std;

int main(){
    char in1[81], in2[81];
    int n;
    cin >> n;
    rep(k,n){
        cin >> in1 >> in2;
        if(strlen(in1) > 80 || strlen(in2) > 80){
            cout << "overflow" << endl;
            break;
        }
        int ans[81] = {0};
        int j = 0;
        for(int i = strlen(in1); i > 0; i--){
            ans[81 - i]+= in1[j] - '0';
            j++;
        }
        j = 0;
        for(int i = strlen(in2); i > 0; i--){
            ans[81 - i]+= in2[j] - '0';
            j++;
        }
        for(int i = 80; i >= 0; i--){
            if(ans[i] >= 10){
                ans[i]-= 10;
                ans[i - 1]++;
            }
        }
        if(ans[0] != 0){
            cout << "overflow" << endl;
            break;
        }
        int len = 80 - max(strlen(in1), strlen(in2)) + 1;
        if(ans[len - 1] != 0)
            cout << ans[len - 1];
        range(i, len, 81){
                cout << ans[i];
        }cout << endl;
    }
}