#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) FOR(i,0,n)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define PQ priority_queue
#define UM unordered_map
#define ALL(a) (a).begin(),(a).end()
#define MOD 1000000007
typedef vector<ll> vi;
typedef vector<vector<ll>> vvi;
const ll INF = (1ll << 30);
typedef pair<ll,ll> pii;
struct Edge{ ll s,t,c; };
typedef vector<vector<ll>> Graph;
typedef vector<pii> vpii;

vi get(ll a) {
  vi ret;
  for(ll i=1;i*2<=a;i++) {
    if(a%i==0) ret.PB(i);
  }
  return ret;
}

int main() {
  ll N,C,V; cin>>N>>C>>V;
  vi A(2*N+1,INF);
  A[1]=0;
  FOR(i,2,2*N+1) {
    vi v=get(i);
    for(ll j:v) {
      A[i]=min(A[i],A[j]+C+V*(i/j-1));
    }
  }
  ll ans=INF;
  FOR(i,N,2*N+1) ans=min(ans,A[i]);
  cout<<ans<<endl;
}