#include<iostream>
#define int long long
using namespace std;
using PII = pair<int, int>;
int t, n;
string k;
signed main() {
//	ios::sync_with_stdio(0);
	cin >> t;
	while (t--) {
		int temp = 0;
		cin >> n >> k;
		temp = stoi(k, 0, n);
		cout << temp << endl;
	}
	return 0;
}