1119_A. Ilya and a Colorful Walk
Ilya lives in a beautiful city of Chordalsk.

There are n houses on the street Ilya lives, they are numerated from 1 to n from left to right; the distance between every two neighboring houses is equal to 1 unit. The neighboring houses are 1 and 2, 2 and 3, ..., n-1 and n. The houses n and 1 are not neighboring.

The houses are colored in colors c_1, c_2, …, c_n so that the i-th house is colored in the color c_i. Everyone knows that Chordalsk is not boring, so there are at least two houses colored in different colors.

Ilya wants to select two houses i and j so that 1 ≤ i < j ≤ n, and they have different colors: c_i ≠ c_j. He will then walk from the house i to the house j the distance of (j-i) units.

Ilya loves long walks, so he wants to choose the houses so that the distance between them is the maximum possible.

Help Ilya, find this maximum possible distance.

Input

The first line contains a single integer n (3 ≤ n ≤ 300 000) — the number of cities on the street.

The second line contains n integers c_1, c_2, …, c_n (1 ≤ c_i ≤ n) — the colors of the houses.

It is guaranteed that there is at least one pair of indices i and j so that 1 ≤ i < j ≤ n and c_i ≠ c_j.

Output

Print a single integer — the maximum possible distance Ilya can walk.

Examples

Input


5
1 2 3 2 3


Output


4


Input


3
1 2 1


Output


1


Input


7
1 1 3 1 1 1 1


Output


4

Note

In the first example the optimal way is to walk from the first house to the last one, where Ilya can walk the distance of 5-1 = 4 units.

In the second example the optimal way is to either walk from the first house to the second or from the second to the third. Both these ways have the distance of 1 unit.

In the third example the optimal way is to walk from the third house to the last one, where Ilya can walk the distance of 7-3 = 4 units. 
```python
import math
from decimal import Decimal
import heapq
def na():
	n = int(input())
	b = [int(x) for x in input().split()]
	return n,b
 
 
def nab():
	n = int(input())
	b = [int(x) for x in input().split()]
	c = [int(x) for x in input().split()]
	return n,b,c
 
 
def dv():
	n, m = map(int, input().split())
	return n,m
 
 
def dva():
	n, m = map(int, input().split())
	a = [int(x) for x in input().split()]
	b = [int(x) for x in input().split()]
	return n,m,b
 
 
def eratosthenes(n): 
	sieve = list(range(n + 1))
	for i in sieve:
		if i > 1:
			for j in range(i + i, len(sieve), i):
				sieve[j] = 0
	return sorted(set(sieve))
 
 
 
def nm():
	n = int(input())
	b = [int(x) for x in input().split()]
	m = int(input())
	c = [int(x) for x in input().split()]
	return n,b,m,c
 
 
def dvs():
	n = int(input())
	m = int(input())
	return n, m 


n,a =na()
d1 =0
d2 =0
for i in range(n):
	if a[i] != a[0]:
		d1 = i
for i in range(n -1, -1, -1):
	if a[i] != a[n - 1]:
		d2 = n - i - 1
print(max(d1, d2))

```