#include <bits/stdc++.h>
using namespace std;
int n;
int a[5][5];
int kq;
void solve() {
  int i;
  int vt, tgvt, kc;
  kq = 0;
  vt = 0;
  while (n > 1) {
    kc = 2147483647;
    for (i = 0; i < 3; i++) {
      if (i != vt) {
        if (a[vt][i] < kc) {
          kc = a[vt][i];
          tgvt = i;
        }
      }
    }
    vt = tgvt;
    kq += kc;
    n--;
  }
}
void output() { printf("%d\n", kq); }
int main() {
  while (scanf("%d", &n) > 0) {
    scanf("%d", &a[0][1]);
    scanf("%d", &a[0][2]);
    scanf("%d", &a[1][2]);
    a[2][1] = a[1][2];
    a[1][0] = a[0][1];
    a[2][0] = a[0][2];
    solve();
    output();
  }
  return 0;
}
