#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,a) FOR(i,0,a)

const int MAX_N=50000;

int N;
int C,V;

int dp[MAX_N+1];

void solve(){
  dp[1]=0;
  FOR(i,2,N+1){
    dp[i]=C+(i-1)*V;
    FOR(j,2,i){
      dp[i]=min(dp[i],dp[j]+C+((i+j-1)/j-1)*V);
    }
  }
  cout<<dp[N]<<endl;
}

int main(){
  cin>>N;
  cin>>C>>V;
  solve();
  return 0;
}