//https://www.facebook.com/CungHocLapTrinhUIT
#include <iostream>
using namespace std;

int GT(int n)
{
	int s = 1;
	for (int i = 1; i <= n; i++)
		s *= i;
	return s;
}

void main()
{
	int a, b, c;
	cin >> a >> b >> c;
	cout << GT(a) + GT(b) + GT(c) << endl;
}