import sequtils,strutils,math
var
    S = stdin.readline
    ans = 0
    p = 0.0
    
while p.int <= S.high:
    var cnt : int
    for i,c in S:
        if (p * 2).int - i < 0:
            break
        if (2 * p).int - i <= S.high and c == S[(2 * p).int - i]:
            cnt += 1
    ans = max(ans, cnt)
    p += 0.5

echo ans