/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2021.06.23 00:29:21
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;




template<typename T>
struct Dijkstra {
private:
    int V;
    struct edge { int to; T cost; };
    vector<vector<edge>> G;
public:
    const T inf = numeric_limits<T>::max();
    
    
    vector<T> d; 
    Dijkstra() {}
    Dijkstra(int V) : V(V) {
        G.resize(V);
    }
    
    Dijkstra<T>& operator=(const Dijkstra<T>& obj) {
        this->V = obj.V;
        this->G = obj.G;
        this->d = obj.d;
        return *this;
    }
    
    
    void add_edge(int from, int to, T weight, bool directed = false) {
        G[from].push_back({to,weight});
        if (!directed) G[to].push_back({from,weight});
    }
    
    
    int add_vertex() {
        G.push_back(vector<edge>());
        return V++;
    }
    void build(int s) {
        d.assign(V, inf); 
        typedef tuple<T, int> P; 
        priority_queue<P, vector<P>, greater<P>> pq;
        d[s] = 0; 
        pq.push(P(d[s], s)); 
        while (!pq.empty()) {
            P p = pq.top(); pq.pop();
            int v = get<1>(p);
            
            if (d[v] < get<0>(p)) continue; 
            for (const edge &e : G[v])
            {
                
                if (d[e.to] > d[v] + e.cost) {
                    d[e.to] = d[v] + e.cost;
                    pq.push(P(d[e.to], e.to));
                }
            }
        }
    }
};
int main() {
    int n;cin >> n;
    int c,v;cin >> c >> v;
    Dijkstra<ll> g(n+1);
    for (int i = 1; i <= n; i++) {
        for (int j = 2; ; j++) {
            g.add_edge(i,min(j*i,n),c+v*(j-1),true);
            if (j*i >= n) break;
        }
    }
    g.build(1);
    cout << g.d[n] << endl;
    return 0;
}