import math
def GetMaxChars(s) :
size = len(s)
maxCh = 0
i = 0
while (i < size - 1) :
j = i + 1
while (j < size) :
if (s[i] == s[j]) :
temp = abs(j - i - 1)
maxCh = maxCh if maxCh > temp else temp
j += 1
i += 1
return maxCh
s = "aBcaaBdefBgh"
print(GetMaxChars(s))
'''
run:
7
'''