#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)n; i++)
using ll = long long;

int main(){
  ll n, a, b;
  cin >> n >> a >> b;
  ll ans = -b*n + a*(n-1);
  ans = min(ans,-a*(n-1)-b*((n+1)/2)+b*(n/2));
  cout << ans << endl;
  return 0;
}