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def judge(ss, i): 
    st, end = 0, len(ss) - 1 
    while st < end:
        if st == i:
            st += 1
        if end == i:
            end -= 1
        if ss[st] != ss[end]:
            return False
        st += 1
        end -= 1
    return True
         
         
ss = raw_input()
for i in range(len(ss)):
    if judge(ss, i): 
        print(i + 1)                                                                                                                                                                                               
        break
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