#include <iostream>
#include <cmath>
using namespace std;
int main() {
unsigned int A, B, C;
cin >> A >> B >> C;
cout << (A*B*C - 1);
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgojaW5jbHVkZSA8Y21hdGg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CgppbnQgbWFpbigpIHsKCXVuc2lnbmVkIGludCBBLCBCLCBDOwoJY2luID4+IEEgPj4gQiA+PiBDOwoJY291dCA8PCAoQSpCKkMgLSAxKTsKCXJldHVybiAwOwp9