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

using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<class t> using vc = vector<t>;
template<class t> using vvc = vc<vc<t>>;
using pi = pair<int,int>;
using vi = vc<int>;
using vvi = vvc<int>;

#define rep(i,a,b) for (int i = a; i < b; i++)
#define irep(i,a,b) for (int i = a; i > b; i--)
#define print(n) cout << n << '\n'
#define pritn(n) print(n)
#define rup(a,b) (a+b-1)/b
#define input(A,N) rep(i,0,N) cin>>A[i];
#define chmin(a,b) a = min(a,b)


int main(){
    cout << fixed << setprecision(15);
    
    ll N ;
    cin >> N;
    ll c,v;
    cin >> c >> v;
    ll inf = ll(pow(10,10));
    vc<ll> dp(N+1,inf);
    dp[1] = 0;
    ll now = 0;
    rep(i,1,N){
        now = i;
        ll cost = dp[i]+c+v;
        ll next = 2*now;
        chmin(dp[min(next,N)],cost);
        while(next<=N){
            next += i;
            cost += v;
            chmin(dp[min(next,N)],cost);
        }
        chmin(dp[min(next,N)],cost);
    }
    print(dp[N]);


    
    //system("pause");
    return 0;
}