n = int(input())
p = input().split()
a = []
for j in range(len(p)):
    i = int(p[j])
    if i == n:
        print(i, ' '.join(map(str,a)))
        n -= len(str(i)) + len(' '.join(map(str,a)))
        a = []

    else:
       print('')
       a.append(i)