#include <iostream>
using namespace std;

int fact(int n)
{
    if (n==0) return 1;
    else return fact(n-1)*n;
}

int ncr(int n, int r)
{
    int num, den;
    num = fact(n);
    den = fact(r)*fact(n-r);
    return num/den;
}

int NCR(int n, int r)  //using recursion
{
    if (n==r || r==0)
        return 1;
    else
        return NCR(n-1, r-1) + NCR(n-1,r);
}

int main() 
{
    cout << ncr(2,0) << endl;
    cout << NCR(5,1);
    return 0;
}