[백준] 27962번 오렌지먹은지오랜지 python

n = int(input())
s = input()
ans = 'NO'

for i in range(1,n):
    a = s[:i]
    b = s[n-i:]
    cnt=0
    for j in range(len(a)):
        if a[j]!=b[j]:
            cnt+=1
    if cnt==1:
        ans='YES'
        break
print(ans)