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

public class Solution {
    
    static long fact(long p){
        long f = 1;
        for(int i = 2; i<=p; i++)
            f*=i;
        return f;
    }

    static long countArray(int n, int k, int x) {
        // Return the number of ways to fill in the array.
        long sum;
        if(x<=k)
            sum = fact(k)-2*k+3;
        else
            sum = fact(k)-k+2;
        return sum;
        
    }

    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();
    }
}