import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int c = sc.nextInt();
    int v = sc.nextInt();
    int[] dp = new int[n + 1];
    dp[1] = 0;
    for(int i = 2; i < n + 1; i++) {
      int a = Integer.MAX_VALUE;
      a = Math.min(a, c + v * (i - 1)); 
      for(int j = 2; j * j <= i; j++) {
        if(i % j == 0) {
          a = Math.min(a, dp[j] + c + v * ((i - j) / j));
        }
      } 
    }
    int ans = Integer.MAX_VALUE;
    for(int i = n; i < 2 * n - 1; i++) {
      ans = Math.min(ans, dp[i]);
    }
    System.out.println(ans);
  }
}