#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int ns=0;
	for (int i=0;i<n;i++)
	{
		int jz;
		string a;
		cin>>jz>>a;
		int b=0;
		int wss=a.size()-1; 
		if (jz==10)
		{
			cout<<a<<endl;
			continue;
		}
		for (int i=0;i<a.size();i++)
		{
			int aa=a[i];
			aa-=48;
			if (jz>9&&aa>9)
			{
				aa-=7;
			}
			b+=(aa*pow(jz,wss));
			wss--;
		}
		cout<<b<<endl;
	}
}