#include<bits/stdc++.h>
using namespace std;  
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
#define rep(i,n) for(ll i=0;i<(n);i++)  
#define pii pair<int,int>
#define piii pair<int,pii>
#define mp make_pair
#define pb push_back  
#define ALL(a) (a).begin(),(a).end()
#define FST first
#define SEC second  
const int INF = (INT_MAX/2);
const ll LLINF = (LLONG_MAX/2);
const double eps = 1e-5;
const double PI = M_PI;  
#define DEB cout<<"!"<<endl
#define SHOW(a,b) cout<<(a)<<" "<<(b)<<endl
#define SHOWARRAY(ar,i,j) REP(a,i)REP(b,j)cout<<ar[a][b]<<((b==j-1)?((a==i-1)?("\n\n"):("\n")):(" "))
  
#define DIV 1000000007
typedef vector<ll> Array;
typedef vector<Array> matrix;

typedef tuple<int,int,int> tiii;
#define mt make_tuple

int dp[100002] = {};

int main(){
  int n,c,v; cin >> n >> c >> v;
  fill_n(dp,100002,INF);
  dp[1] = 0;
  for(int i = 1;i < n; i++)
    for(int j = 1; i+j*i < 100002; j++)
      dp[i+j*i] = min(dp[i+j*i],dp[i] + c + v*j);
  int ans = INF;
  for(int i = n; i < 100002; i++)
    ans = min(ans,dp[i]);
  cout << ans << endl;
  return 0;
}