/* -*- coding: utf-8 -*-
 *
 * 555.cc: No.555 世界史のレポート - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 50000;
const int MAX_N2 = MAX_N * 2;
const int INF = 1 << 30;

/* typedef */

/* global variables */

int dp[MAX_N2];

/* subroutines */

inline void setmin(int &a, int b) { if (a > b) a = b; }

/* main */

int main() {
  int n, c, v;
  cin >> n >> c >> v;
  int n2 = n * 2;
  
  dp[1] = 0;
  for (int i = 2; i < n2; i++) {
    int mind = INF;
    for (int j0 = 1; j0 * j0 <= i; j0++)
      if (i % j0 == 0) {
	int j1 = i / j0;
	setmin(mind, dp[j0] + c + (j1 - 1) * v);
	if (j1 != j0 && j1 < i)
	  setmin(mind, dp[j1] + c + (j0 - 1) * v);
      }
    dp[i] = mind;
  }

  int mind = INF;
  for (int i = n; i < n2; i++)
    setmin(mind, dp[i]);
  printf("%d\n", mind);
  return 0;
}