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

int main(){
    ll n, a, b, c1, c2, ans = 1ll << 60;
    cin >> n >> a >> b;
    c1 = n / 2, c2 = n - c1;
    ans = min(ans, -a * (n - 1) + b * (c2 - c1));
    ans = min(ans, -a * (n - 1) + b * (c1 - c2));
    ans = min(ans, a * (n - 1) + b * (- n));
    for(ll i = 1; i * i <= 10000 * n; i++){
        c1 = n / i, c2 = n - c1;
        if(c2 < 0)break;
        ll d = min(2 * min(c1, c2), n - 1);
        ans = min(ans, a * (-d + (n - 1 - d)) + b * (c1 - c2));
        ans = min(ans, a * (-d + (n - 1 - d)) + b * (c2 - c1));
    }
    cout << ans << endl;
}