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