#include<cstdio>
#include<queue>


using namespace std;
using vi=vector<int>;


struct q_t
{
	int c, cn, n;

	bool operator<(const q_t&rhs) const
	{
		return c>rhs.c;
	}
};


class que_t
{
	priority_queue<q_t> q;
public:
	void push(int c, int cn, int n)
	{
		q.push((q_t){c, cn, n});
	}
	bool pop(int&c, int&cn, int&n)
	{
		if(q.empty()) return false;
		c=q.top().c;
		cn=q.top().cn;
		n=q.top().n;
		q.pop();
		return true;
	}
};


int solve(int n, int c, int v)
{
	que_t q;
	int rc=0, rcn=0, rn=1;

	q.push(rc, rcn, rn);
	while(q.pop(rc, rcn, rn))
	{
//printf("c=%d  cn=%d  n=%d\n", rc, rcn, rn);
		if(rn>=n) return rc;
		q.push(rc+c+v, rn, rn+rn);
		if(rcn>0) q.push(rc+v, rcn, rn+rcn);
	}
	return -1;
}


int main(void)
{
	int n, c, v;

	while(scanf("%d%d%d", &n, &c, &v)==3)
	{
		printf("%d\n", solve(n, c, v));
	}

	return 0;
}