#include<bits/stdc++.h>
using namespace std;
#include <unordered_set>
#include <random>
//#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll inv2=499122177;
const ll MAX=200010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;

ll dx[]={0,1,0,-1,-1,-1,1,1};
ll dy[]={1,0,-1,0,-1,1,-1,1};

string u="RDLU";

void solve(){
    ll N,A,B;
    cin>>N>>A>>B;
    ll ans=(N-1)*A-N*B;
    if(N>=10000){
        ans+=(N/2)*2*B-2*(N-1)*A;
    }else{
        ll mi=0;
        REP(i,1,N){
            mi=min(mi,((i+1)/2)*2*B-2*i*A);
        }
        ans+=mi;
    }
    cout<<ans<<endl;
}

signed main(){
    //cin.tie(0);
    //ios::sync_with_stdio(false);
    solve();
}