#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int r = 1, o = 0, e = 0;
  int n;
  cin >> n;
  n--;
  int a, b, c;
  cin >> a >> b >> c;
  int res = 0;
  while (n > 0) {
    if (r == 1) {
      if (a < b) {
        res += a;
        o = 1;
      } else {
        res += b;
        e = 1;
      }
      r = 0;
    } else if (o == 1) {
      if (a < c) {
        res += a;
        r = 1;
      } else {
        res += c;
        e = 1;
      }
      o = 0;
    } else if (e == 1) {
      if (b < c) {
        res += b;
        r = 1;
      } else {
        res += c;
        o = 1;
      }
      e = 0;
    }
    n--;
  }
  cout << res << endl;
}
