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

ll N, C, V;

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

  ll dp[200001];
  REP(i, 0, 200001) dp[i] = INF;
  dp[1] = 0;

  REP(i, 2, 2 * N - 1) {
    ll r = sqrt((double) i) + 10;
    REP(j, 1, r) {
      if(i % j == 0) {
        dp[i] = min(dp[i], dp[j] + C + V * (i / j - 1));
      }
    }
  }

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