#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>  
using namespace std;
#define eps 0.00000001
#define LONG_INF 10000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
long long n;
long long c, v;
int main() {
	cin >> n >> c >> v;
	long long ans = 1000000000000;
	for (int i = 0;i < n;++i) {
		long long now_length = 100000;
		for (int q = 1;q < n+2;++q) {
			long long now = 1;
			long long stock = 1;
			for (int j = 0;j >= 0;++j) {
				stock += now;
				if ((j + 1) % q == 0&&(j+1)/q <= i) {
					now = stock;
				}
				if (stock >= n) {
					if (now_length > j+1) {
						now_length = j+1;
						break;
					}
					else goto ending;
				}
			}
		}
	ending:;
		ans = min(ans, now_length*v + c*i);
	}
	cout << ans+c << endl;
	return 0;
}