#include <bits/stdc++.h>
using namespace std;
long long n, a, b, c;
int main() {
  long long i;
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> a >> b >> c;
  long long sum = 0;
  string str = "rabbit";
  for (i = 0; i < n - 1; i++) {
    if (str == "rabbit") {
      sum += min(a, b);
      long long x = min(a, b);
      if (x == a) {
        str = "owl";
      } else {
        str = "egor";
      }
    } else if (str == "owl") {
      sum += min(a, c);
      long long x = min(a, c);
      if (x == a) {
        str = "rabbit";
      } else {
        str = "egor";
      }
    } else if (str == "egor") {
      sum += min(b, c);
      long long x = min(b, c);
      if (x == b) {
        str = "rabbit";
      } else {
        str = "owl";
      }
    }
  }
  cout << sum << endl;
  return 0;
}
