#include <iostream> #include <cstring> using namespace std; int main(){ char str[64]; int r; cin>>r>>str; long long len=strlen(str),s=0; for(int i=0;i<len;i++){ if(str[i]>='A') s=s*r+str[i]-'A'+10; else s=s*r+str[i]-'0'; } cout<<s; return 0; }