S=input()

n=len(S)

DP=[1 for _ in range(n+1)]

DP[0]=len(S)
s_to_n={chr(i+97):i for i in range(26)}

def is_kaibun(s):
    n=len(s)
    for i in range(n//2):
        if s[i]!=s[n-1-i]:
            return 0
    return 1

for i in range(n):
    cnt=1<<s_to_n[S[i]]
    for j in range(i+1,n):
        s=S[j]
        cnt^=1<<s_to_n[s]
        if (j+i)%2==0 and cnt^(1<<s_to_n[S[(i+j)//2]])==0:
            if is_kaibun(S[i:j+1]):
                DP[j+1]=max(min(DP[i],j-i+1),DP[j+1])
        elif (j+i)%2==1 and cnt==0:
            if is_kaibun(S[i:j+1]):
                DP[j+1]=max(min(DP[i],j-i+1),DP[j+1])

print(DP[-1])