#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int n, a, b, c, res = 0, i;
  char now = 'r';
  cin >> n >> a >> b >> c;
  for (i = 1; i < n; i++) {
    if (now == 'r') {
      now = (a < b) ? 'o' : 'e';
      res += min(a, b);
    } else if (now == 'o') {
      now = (a < c) ? 'r' : 'e';
      res += min(a, c);
    } else {
      now = (b < c) ? 'r' : 'o';
      res += min(b, c);
    }
  }
  cout << res << endl;
}
