#include <bits/stdc++.h>
using namespace std;
int ans;
int main() {
  int n, a, b, c, now;
  scanf("%d", &n);
  scanf("%d %d %d", &a, &b, &c);
  now = 1;
  while (--n) {
    if (now == 1) {
      if (a < b)
        ans += a, now = 2;
      else
        ans += b, now = 3;
    } else if (now == 2) {
      if (a < c)
        ans += a, now = 1;
      else
        ans += c, now = 3;
    } else {
      if (b < c)
        ans += b, now = 1;
      else
        ans += c, now = 2;
    }
  }
  printf("%d\n", ans);
  return 0;
}
