#include<bits/stdc++.h>
using namespace std;
string s;
int n,k,d,jz=1,ans;
int main()
{
cin>>n;
for(int i=1;i<=n;i++)
{

ans=0;
jz=1;
cin>>k>>s;
for(int i=s.size()-1;i>=0;i--)
{
if(isdigit(s[i]))ans+=(s[i]-48)*jz;
else ans+=(s[i]-'A'+10)*jz;
jz*=k;
}
cout<<ans<<endl;
}
return 0;
}