求救

#include<iostream>
#include<cstring>
using namespace std;
int main(){
    int t,n;
    string a;
    cin>>t;
    while(t--){
        unsigned int wq=1,sum=0;
        cin>>n>>a;
        for(int i=int(a.length())-1;i>=0;i--){
            int b=0;
            if(a[i]>='A' && a[i]<='F')b=a[i]-'A'+10;
            else b=a[i]-'0';
            sum+=b*wq;
            wq*=n;
        }
        cout<<sum<<endl;
    }
    return 0;
}