#include "bits/stdc++.h"

using namespace std;

using ll = long long int;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vd = vector<double>;
using vvd = vector<vd>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vs = vector<string>;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { -1, 0, 1, 0 };
const int dy[] = { 0, 1, 0, -1 };

int gcd(int x, int y) { return y ? gcd(y, x % y) : x; }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
int lcm(int x, int y) { return x / gcd(x, y) * y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	ll n, c, v;
	cin >> n >> c >> v;

	vl dp(2 * n + 1, INF64);
	dp[1] = 0;
	for (int i = 1; i <= n; i++) {
		for (int x = 2; i * x <= 2 * n; x++) {
			dp[i * x] = min(dp[i * x], dp[i] + c + v * (x - 1));
		}
	}

	ll res = INF;
	for (int i = n; i < 2 * n; i++) {
		res = min(res, dp[i]);
	}
	cout << res << endl;
	return 0;
}