#include <iostream>
#include <vector>
using namespace std;
const int INF = 1000000000;
int main(){
	int N;
	cin >> N;
	int C, V;
	cin >> C >> V;
	vector<int> dp(N * 2, INF);
	dp[1] = 0;
	for (int i = 1; i <= N; i++){
		for (int j = i * 2; j < N * 2; j += i){
			dp[j] = min(dp[j], dp[i] + C + (j / i - 1) * V);
		}
	}
	int ans = INF;
	for (int i = N; i < N * 2; i++){
		ans = min(ans, dp[i]);
	}
	cout << ans << endl;
}