#include <bits/stdc++.h>

using namespace std;


long countArray(int n, int k, int x) {
    long num = 1,deno = 1;
    for(int i=1;i<k;i++)
        deno = deno*i;
    for(int i=k;i>1;i--)
        num = num*i;
    long result = num/deno;
    return result;
}

int main() {
    int n;
    int k;
    int x;
    cin >> n >> k >> x;
    long answer = countArray(n, k, x);
    cout << answer << endl;
    return 0;
}