class Node:
    def __init__(self, x):
        self.x = x
        self.prev = None
        self.next = None


class LinkedList:
    def __init__(self):
        self.front = Node(None)
        self.back = self.front
        pass

    def append(self, x):
        node = Node(x)
        node.prev = self.back
        self.back.next = node
        self.back = node
        return node

    def appendleft(self, x):
        front = self.front
        node = Node(x)
        next = front.next
        if next is None:
            node.prev = front
            front.next = node
        else:
            next.prev = node
            node.next = next

            node.prev = front
            front.next = node

        self.front = node
        return node

    def remove(self, node: Node):
        prev = node.prev
        next = node.next
        assert prev is not None
        prev.next = next
        if next is not None:
            next.prev = prev


N = int(input())
P = list(map(lambda x: int(x)-1, input().split()))

ll = LinkedList()
d = {}
for p in P:
    node = ll.append(p)
    d[p] = node

used = set()
ans = []
for i in range(N):
    if i in used: continue
    node = d[i]
    next = node.next
    if next is None: continue
    ans.append(node.x + 1)
    ans.append(next.x + 1)
    used.add(node.x)
    used.add(next.x)
    ll.remove(node)
    ll.remove(next)

print(*ans)