#include <iostream>
#include <algorithm>
using namespace std;
#define repeat(i,n) for (int i = 0; i < (n); ++i)
#define MAX_DIGIT (80)
int d[MAX_DIGIT+1];
int main() {
    int N; cin >> N;
    repeat (test,N) {
        fill(d,d+MAX_DIGIT+1,0);
        repeat (i,2) {
            string s; cin >> s;
            if (80 < s.length()) {
                cout << "overflow" << endl;
                if (i == 0) cin >> s;
                goto next;
            }
            repeat (j,(int)s.length()) {
                d[j] += s[s.length()-1-j] - '0';
            }
        }
        repeat (i,MAX_DIGIT) {
            d[i+1] += d[i] / 10;
            d[i] %= 10;
        }
        if (d[MAX_DIGIT] != 0) {
            cout << "overflow" << endl;
        } else {
            int i = MAX_DIGIT;
            while (d[i] == 0) -- i;
            for (; 0 <= i; --i) cout << d[i];
            cout << endl;
        }
next: ;
    }
    return 0;
}