#include <bits/stdc++.h>
using namespace std;

#define FOR(i,l,r) for(int i = int(l);i < int(r);i++)
template<typename T> bool chmax(T& a,const T& b){ return a < b ? (a = b,true) : false; }
template<typename T> bool chmin(T& a,const T& b){ return b < a ? (a = b,true) : false; }
typedef long long ll;

int N,C,V;
const int MAX_N = 50000;
ll dp [MAX_N + 1];
const ll INF = 1e18;

int main()
{
	cin >> N >> C >> V;

	fill(dp,dp + MAX_N + 1,INF);
	dp [1] = 0;
	FOR(i,1,N){
		for(int j = i * 2,k = 1;;j += i,k++){
			chmin(dp [min(N,j)],dp [i] + C + (ll) V * k);
			if(j >= N) break;
		}
	}

	cout << dp [N] << endl;

	return 0;
}