import java.util.Scanner;
public class Ohjelma {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int m = s.nextInt();
int[] a = new int[m+1];
// String[] ss = s.nextLine().split(" ");
//
// for (int i = 0; i < ss.length; i++) {
// a[i] = Integer.parseInt(ss[i]);
//
// }
//
for (int i = 0; i<=m; i++) {
a[i] = s.nextInt();
System.out.println("i: " + i + " a[i]: " + a[i]);
}
int max = 0;
for (int i = 0; i < a.length; i++) {
for(int j = 0; j < a.length; j++){
int sum = a[i] + a[j];
System.out.println("i: " + i + " j: "+ j + " sum: " + sum);
if(m-i-j < 0) continue;
for (int l = m-(i+j); l>= 0; l--){
int res = sum + a[l];
System.out.println("res: " + res);
if(res > max){
max = res;
System.out.println(max);
}
}
}
}
System.out.println(" HEI" + max);
}
}