#include <bits/stdc++.h>

using namespace std;

const int INF = 1e9;

int dp[50005];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n, c, v;
	cin >> n >> c >> v;
	for (int i = 2; i <= n; i++) {
		dp[i] = INF;
	}

	for (int i = 1; i < n; i++) {
		for (int j = 1; j < (n + i - 1) / i; j++) {
			dp[min(i * (j + 1), n)] = min(dp[min(i * (j + 1), n)], dp[i] + c + v * j);
		}
	}
	cout << dp[n] << endl;
	return 0;
}