/* -*- 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 INF = 1 << 30;

/* typedef */

/* global variables */

int dp[MAX_N + 1];

/* subroutines */

/* main */

int main() {
  int n, c, v;
  cin >> n >> c >> v;

  dp[1] = 0;
  for (int i = 2; i <= n; i++) {
    int mind = INF;
    for (int j = 1; j < i; j++) {
      int d = dp[j] + c + (i - 1) / j * v;
      if (mind > d) mind = d;
    }
    dp[i] = mind;
  }

  printf("%d\n", dp[n]);
  return 0;
}