// {{{ Templates
#include <bits/stdc++.h>

#define show(x) cerr << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz:" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = (ll)1e9 + 7LL;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

// }}}

struct Info {
    int len;
    int clip;
    ll cost;
};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    ll C, V;
    cin >> C >> V;

    vector<ll> dp(2 * N + 1, INF<ll>);
    dp[1] = 0;

    for (int i = 1; i <= N; i++) {
        for (int d = 2; d * i <= 2 * N; d++) {
            dp[i * d] = min(dp[i * d], dp[i] + (d - 1) * V + C);
        }
    }
    ll mincost = INF<ll>;
    for (int i = N; i <= 2 * N; i++) {
        mincost = min(mincost, dp[i]);
    }
    cout << mincost << endl;


    return 0;
}