with open('daykhonglap.inp') as f:
    n = int(f.readline())
    x = f.read()
b = x.split()
a = list(map(int,b))
d = m = 0
s = {}
for i in range(n):
    z = a[i]
    if z in s:
        d = max(d,s[z]+1)
    m = max(m,i-d+1)
    s[z] = i
with open('daykhonglap.out','w') as f:
    f.write(str(m))