#include<iostream>
#include<iomanip>
#include<math.h>
#include<vector>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<complex>

#define INF (long long)1000000000
#define MOD 1000000007
#define EPS 1e-8

#define REP(i, m) for(long long i = 0; i < m; ++i)
#define FOR(i, n, m) for(long long i = n; i < m; ++i)
#define ALL(v) v.begin(), v.end()
#define pb push_back

using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
typedef long double ld;

int n,c,v;

ll rec(ll dig, ll cl) {
	if(dig>=n) return 0;
	else {
		if(dig==cl) return (rec(dig+cl,cl)+v);
		else {
			return min(rec(dig+cl,cl)+v,rec(dig,dig)+c);
		}
	}
}

int main() {
	cin>>n>>c>>v;
	cout<<c+rec(1,1)<<endl;
}