#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int r_o, r_e, o_e;
  cin >> n >> r_o >> r_e >> o_e;
  int dis = 0;
  if (n <= 1)
    goto ans;
  else {
    n--;
    char curr = 'r';
  again:;
    if (curr == 'r') {
      if (n == 0) goto ans;
      if (r_o < r_e) {
        dis += r_o;
        curr = 'o';
      } else {
        dis += r_e;
        curr = 'e';
      }
      n--;
      goto again;
    }
    if (curr == 'o') {
      if (n == 0) goto ans;
      if (r_o < o_e) {
        dis += r_o;
        curr = 'r';
      } else {
        dis += o_e;
        curr = 'e';
      }
      n--;
      goto again;
    }
    if (curr == 'e') {
      if (n == 0) goto ans;
      if (r_e < o_e) {
        dis += r_e;
        curr = 'r';
      } else {
        dis += o_e;
        curr = 'o';
      }
      n--;
      goto again;
    }
  }
ans:;
  cout << dis << endl;
  return 0;
}
