#include <bits/stdc++.h>

using namespace std;

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

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