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

int main() {
int N;
cin >> N;
for (; N > 0; --N) {
int a[80] = {}, b[80] = {}, sum[80] = {};
bool co = false;
string s, t;
cin >> s >> t;
for (int i = 0; i < s.length(); ++i) a[i] = (int)(s[i] - '0');
for (int i = 0; i < t.length(); ++i) b[i] = (int)(t[i] - '0');
for (int i = 0; i < 80; ++i) {
co = ((co?1:0)+a[i]+b[i]) >= 10;
sum[i] = ((co?1:0)+a[i]+b[i])%10;
}
if (co) cout << "overflow" << endl;
else {
bool fz = true;
for (int i = 79; i >= 0; --i) {
if (fz && sum[i] != 0) {fz = false;}
if (!fz) cout << sum[i];
}
}
cout << endl;
}
return 0;
}