#include <iostream>
using namespace std;
int factorial(int x)
{
int p = 1;
while (x)
{
p *= x;
x--;
}
return p;
}
int main()
{
int n, k, C;
cin >> n >> k;
//C_n luate cate k = n! / (k!(n-k)!)
cout << fact(n) / (fact(k) * fact(n - k));
//Exista o metoda mai buna cu programare dinamica :)
}
