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

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

#define fi first
#define se second
#define repl(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define rep(i,n) repl(i,0,n)
#define each(itr,v) for(auto itr:v)
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define mmax(x,y) (x>y?x:y)
#define mmin(x,y) (x<y?x:y)
#define maxch(x,y) x=mmax(x,y)
#define minch(x,y) x=mmin(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt __builtin_popcount

#define INF 1e16

ll n;
ll c,v;
ll dp[100010];

int main(){
	cin.sync_with_stdio(false);
  cin>>n;
  cin>>c>>v;
  rep(i,100010)dp[i]=INF;
  dp[1]=0;
  repl(i,1,n+1){
    for(ll j=i*2;j<=2*n;j+=i){
      minch(dp[j],dp[i]+c+((j/i)-1)*v);
    }
  }
  cout<<*min_element(dp+n,dp+100010)<<endl;
	return 0;
}