#include<iostream>

using namespace std;

int fact(int);

long double Series(int,int);

int N,K;

int main()

{

cout<<"Enter 2 Numbers followed by space "; cin>>N>>K;

cout<<"Series = "<<Series(N,K)<<endl;

return 0;

}

//Factorial Calculator

int fact(int N)

{

int Num = 1;

for (int i=1; i<=N; i++)

Num *= i;

return Num;

}

//Series Calculator

long double Series(int N,int K)

{

return ((fact (N))/((fact(K))*(fact(N-K))));

}