#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int N = 50000;
int n,c, v,dp[N+1];
int main() {
	memset(dp, 1, sizeof(dp));
	dp[1] = 0;
	cin >> n >> c >> v;
	for (int i = 1; i <= n; i++) {
		for (int j = 2;; j++) {
			dp[min(j*i, n)] = min(dp[min(j*i, n)], dp[i] + c + v * (j - 1));
			if (j*i >= n)break;
		}
	}
	cout << dp[n] << endl;
	return 0;
}