nCr

#include<stdio.h>
int main()
{int n,r,z,x=1;
int y=1;
scanf("%d %d",&n,&r);
while (r>0)
    {x=x*n;
    n=n-1;
    y=y*r;
    r=r-1;}
z=x/y;
printf("%d",z);}