#include <iostream>
using namespace std;
using ll = long long;

int main(){
    ll n, a, b; cin >> n >> a >> b;
    ll ans = (n-1)*a-n*b;
    if(ans > -(n-1)*a-(n%2)*b) ans = -(n-1)*a-(n%2)*b;
    cout << ans << endl;
    return 0;
}