#include<iostream>
using namespace std;
int main()
{ long long int n=4, k=2, Pn=1, Akn=1, Ckn=1;
  for (int j=2; j<=n; j++) Pn *=j;
  for (int j=1; j<=k; j++) Akn*=(n-j+1);
  for (int j=1; j<=k; j++) Ckn=(Ckn*(n-j+1))/j;
  cout<<"  P_"<<n<<" = "<<Pn<<endl;
  cout<<"A^"<<k<<"_"<<n<<" = "<<Akn<<endl;
  cout<<"C^"<<k<<"_"<<n<<" = "<<Ckn<<endl;
  return 0;
}