#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second
template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> pip;
const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-10;
const bool debug = 0;
//---------------------------------//

int N, C, V;
int dp[112345];

int main() {
	cin >> N >> C >> V;
	
	fill(dp, dp + 112345, INF);
	dp[1] = 0;
	
	FOR(i, 1, N) {
		chmin(dp[i + i], dp[i] + C + V);
		for (int j = 2; i * j < N; j++) chmin(dp[i * j], dp[i] + C + V * (j - 1));
		int j = (N + i - 1) / i;
		chmin(dp[i * j], dp[i] + C + V * (j - 1));
	}
	
	cout << *min_element(dp + N, dp + 112345) << endl;
	
	return 0;
}