#include <cmath>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <functional>
#include <queue>
#include <iostream>
#include <string.h>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <cstdint>
#include <climits>
#include <unordered_set>
#include <sstream>
#include <stack>

using namespace std;

typedef long long int ll;
typedef pair<int,int> pii;

int main()
{
    ll n;
    cin >> n;
    ll c, v;
    cin >> c >> v;
    
    ll minCost = 1e15;
    for(int i = 1;i <= 32;i++)
    {
        ll count = 1;
        ll cost = 0;
        ll crip = 0;
        for(int j = 0;j < i;j++)
        {
            crip = count;
            cost += c;
            count += crip;
            cost += v;
            if(count >= n)
            {
                break;
            }
        }
        if(count < n)
        {
            ll aa = (n-count) / crip;
            if((n - count) % crip > 0)
            {
                aa++;
            }
            cost += aa * v;
        }
        //cout << i << "," << count << "," << cost << endl;
        minCost = min(minCost, cost);
    }
    cout << minCost << endl;
    return 0;
}