R=range
S=input()
N=len(S)
P=[0]*N
P[0]=[1]*2
for i in R(1,N):P[i]=[1if i<=j else(S[j]==S[i])*P[i-1][j+1]for j in R(i+2)]
D=[0]*N
D+=[N]
for i in R(N):
	for j in R(i+1):D[i]=max(D[i],min(D[j-1],i-j+1)*P[i][j])
print(D[-2])