#include <iostream>
#include <cstring>
using namespace std;

void storeReverse(char ch[], string str){
    for (int i=0; i<str.size(); i++) {
        ch[i] = str[str.size()-i-1];
    }
}

void calcSum(char ch1[], char ch2[]){
    int c = 0;
    int result[80];
    for (int i=0; i<80; i++) {
        int num1 = ch1[i] - '0';
        int num2 = ch2[i] - '0';
        int sum = num1 + num2 + c;
        if (sum >= 10) {
            sum %= 10;
            c = 1;
        }else{
            c = 0;
        }
        result[i] = sum;
    }
    if (c == 1){
        cout << "overflow" << endl;
    }else{
        int idx;
        for (int i=80-1; i>=0; i--) {
            if (result[i] != 0){
                idx = i;
                break;
            }
        }
        for (int i=idx; i>=0; i--) {
            cout << result[i];
        }
        cout << endl;
    }
}

int main()
{
    int n;
    char ch1[80], ch2[80];
    string str1, str2;
    
    cin >> n;
    for (int i=0; i<n; i++) {
        cin >> str1;
        cin >> str2;
        for (int j=0; j<80; j++) {
            ch1[j] = '0';
            ch2[j] = '0';
        }
        storeReverse(ch1, str1);
        storeReverse(ch2, str2);
        calcSum(ch1, ch2);
        
    }

    return 0;
}