import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    private static long[] cache = new long[1000];

    static long countArray(int n, int k, int x) {
        // Return the number of ways to fill in the array.
        return fattoriale(k) / (fattoriale(k-n+2) * fattoriale(n-2));
    }

    static long fattoriale(int n){
        if(cache[n] != 0)
            return cache[n];
        if(n<=1){
            cache[0]=1;
            cache[1]=1;
            return cache[1];
        }
        cache[n] = fattoriale(n-1) * n;
        return  cache[n];
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        int x = in.nextInt();
        long answer = countArray(n, k, x);
        System.out.println(answer);
        in.close();
    }
}