#include <iostream>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
#define INF 1000000000LL
using namespace std;
typedef long long ll;

ll N, C, V;

int main(void) {
  cin >> N >> C >> V;

  ll dp[100000];
  REP(i, 0, 100000) dp[i] = INF;
  dp[1] = 0;

  REP(i, 1, N) {
    ll cost = dp[i] + C + V;
    for(ll j = i * 2; j < 100000; j += i) {
      dp[j] = min(dp[j], cost);
      cost += V;
    }
  }

  ll ans = INF;
  REP(i, N, 2 * N - 1) ans = min(ans, dp[i]);
  cout << ans << endl;
}