class UnionFind:
    def __init__(self, n):
        self.n = n
        self.par = [-1] * n
        self.group_ = n
        self.R = [i for i in range(n)]

    def find(self, x):
        if self.par[x] < 0:
            return x
        lst = []
        while self.par[x] >= 0:
            lst.append(x)
            x = self.par[x]
        for y in lst:
            self.par[y] = x
        return x

    def unite(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return False

        if self.par[x] > self.par[y]:
            x, y = y, x

        self.par[x] += self.par[y]
        self.par[y] = x
        self.R[x] = max(self.R[x], self.R[y])
        self.group_ -= 1
        return True

    def size(self, x):
        return -self.par[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    @property
    def group(self):
        return self.group_


n = int(input())
P = list(map(int, input().split()))
for i in range(n):
    P[i] -= 1

invP = [0] * n
for i in range(n):
    invP[P[i]] = i

Q = []

p = 0
UF = UnionFind(n)
used = [False] * n
while p < n:
    if used[p]:
        p += 1
        continue

    x = invP[p]
    if UF.R[UF.find(x)] == n - 1:
        p += 1
        continue

    y = UF.R[UF.find(x)] + 1
    q = P[y]
    Q += [p + 1, q + 1]
    UF.unite(x, x - 1)
    UF.unite(y, y - 1)
    used[p] = True
    used[q] = True

print(*Q)