#include <iostream>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

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

  auto f = [&](long long i) {
    long long clip = 0;
    long long len = 1;
    long long cost = 0;
    for (int j = 0; j < i; j++) {
      clip = len; cost += c;
      len += clip; cost += v;
      if (len >= n) {
        return cost;
      }
    }
    clip = len;
    cost += c;
    while (len < n) {
      len += clip;
      cost += v;
    }
    return cost;
  };

  long long ans = 1e18;
  for (int i = 0; i <= 100; i++) {
    ans = min(ans, f(i));
  }

  cout << ans << endl;
}