#include <bits/stdc++.h>
using namespace std;
int a[5][5], n, ans, wz = 1;
int main() {
  int x;
  scanf("%d%d%d%d", &n, &a[1][2], &a[1][3], &a[2][3]);
  a[2][1] = a[1][2];
  a[3][1] = a[1][3];
  a[3][2] = a[2][3];
  for (int i = 1; i <= n - 1; i++) {
    if (wz == 1) {
      if (a[wz][2] <= a[wz][3]) {
        ans += a[wz][2];
        wz = 2;
      } else {
        ans += a[wz][3];
        wz = 3;
      }
    } else if (wz == 2) {
      if (a[wz][1] <= a[wz][3]) {
        ans += a[wz][1];
        wz = 1;
      } else {
        ans += a[wz][3];
        wz = 3;
      }
    } else if (wz == 3) {
      if (a[wz][2] <= a[wz][1]) {
        ans += a[wz][2];
        wz = 2;
      } else {
        ans += a[wz][1];
        wz = 1;
      }
    }
  }
  printf("%d", ans);
  return 0;
}
