n=int(input())
s=input()
if n%2:
	print("YES")
	exit()
for i in range(n//2):
	if s[i]==s[~i]:
		print("YES")
		exit()
for i in range(1,n//2):
	if s[i-1]+s[i]==s[~i]+s[(~i)+1]:
		print("YES")
		exit()
print("NO")