#include <bits/stdc++.h>
using namespace std;
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int n, a, b, c;
  cin >> n >> a >> b >> c;
  long long int curr = 1, sum = 0;
  for (int i = 0; i < n - 1; i++) {
    if (curr == 1) {
      if (a == min(a, b)) {
        curr = 2;
        sum += a;
      } else {
        curr = 3;
        sum += b;
      }
    } else if (curr == 2) {
      if (a == min(a, c)) {
        curr = 1;
        sum += a;
      } else {
        curr = 3;
        sum += c;
      }
    } else {
      if (b == min(b, c)) {
        curr = 1;
        sum += b;
      } else {
        curr = 2;
        sum += c;
      }
    }
  }
  cout << sum << endl;
  return 0;
}
