#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;


int main(){
    ll n, c, v;
    cin >> n >> c >> v;

    VL dp(2*n+1, 1e18);
    dp[1] = 0;
    FOR(i,1,n){
        for (int j = 1; i * (j+1) <= 2*n; j++){
            dp[i * (j+1)] = min(dp[i * (j+1)], dp[i] + c + v*j);
        }
    }
    ll ans = 1e18;
    FOR(i,n,2*n) ans = min(ans, dp[i]);
    cout << ans << endl;
    return 0;
}