#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ll n, a, b, ans = 1ll << 60;
    cin >> n >> a >> b;
    ans = min(ans, -a * (n - 1) + b * (-(n + 1) / 2 + n / 2));
    ans = min(ans, a * (n - 1) + b * (- n));
    cout << ans << endl;
}