def one_str():
    return input()

def many_int():
    return list(map(int, input().split()))

from collections import deque

input_count = 0
N = int(input())
A = many_int()

deq = deque([])
sets = set([])
maxs = 0
for a in A:
    if a in sets:
        maxs = max(len(deq),maxs)
        while deq:
            temp = deq.popleft()
            if temp==a:
                break
            sets.remove(temp)
                
                
    else:
        sets.add(a)
        deq.append(a)

print( max(len(deq),maxs))