#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
#define INF 1e9
using namespace std;
typedef long long ll;

ll N,C,V;

int main(void) {
    cin >> N >> C >> V;

    ll MAX = 2*N-1;
    vector<ll> dp(2*N);
    fill(dp.begin(), dp.end(), INF);
    dp[1] = 0;

    REP(i, 1, N) {
        ll cost = dp[i] + C + V;
        for (ll j = i * 2; j < MAX; j += i) {
            dp[j] = min(dp[j], cost);
            cost += V;
        }
    }

    ll ans = INF;
    REP(i, N, MAX) ans = min(ans, dp[i]);
    cout << ans << endl;
    return 0;
}