#include <iostream> #include <cstring> #include <cmath> using namespace std; int main(){ char str[64]; int r; cin>>r>>str; long long len=strlen(str),s=0,x=0; for(int i=len-1;i>=0;i--){ if(str[i]>='A') str[i]-=7; s+=(str[i]-'0')*pow(r,x); x++; } cout<<s; return 0; }