#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

int main(){
	
	long long n,h,w;
	cin>>n>>h>>w;
	
	long long x = n/2;
	long long y = n-x;
	
	long long ans = (h-1) * x * y;
	ans += (w-1) * x * y;
	
	cout<<ans<<endl;
	
	return 0;
}