N=int(raw_input())
A=[int(raw_input()) for i in range(N)]
Ans=[-1 for i in range(N)]

for i in range(N):
    m,k=-1,-1
    for j,a in enumerate(A):
        if Ans[j]==-1 and a!=i and a>m:
            m,k=a,j
    if m==-1:
        print -1
        exit()
    Ans[k]=i
for a in Ans:
    print a