#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int a, b, c;
  int sum = 0;
  scanf("%d", &n);
  scanf("%d%d%d", &a, &b, &c);
  if (n == 1) {
    printf("0\n");
    return 0;
  } else {
    int val;
    if (a <= b) {
      sum += a;
      val = a;
    } else {
      sum += b;
      val = b;
    }
    for (int i = 3; i <= n; i++) {
      sum += min(val, c);
    }
  }
  printf("%d\n", sum);
  return 0;
}
