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

public class Solution {

    static long countArray(long n, long k, long x) {
       long count=((n-3)*(k-1))+(k-2);
        return count;
        
    }

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