def find_last(string_search, string_target):
position = 0
while position != -1:
position = string_search.find(string_target, position+1 )
if position != -1:
end_pos = position
return end_pos
print find_last("aaaa","a")
ZGVmIGZpbmRfbGFzdChzdHJpbmdfc2VhcmNoLCBzdHJpbmdfdGFyZ2V0KToKICAgICAgICBwb3NpdGlvbiA9IDAKCXdoaWxlIHBvc2l0aW9uICE9IC0xOgogICAgICAgICAgICAgICAgcG9zaXRpb24gPSBzdHJpbmdfc2VhcmNoLmZpbmQoc3RyaW5nX3RhcmdldCwgcG9zaXRpb24rMSApCiAgICAgICAgICAgICAgICBpZiBwb3NpdGlvbiAhPSAtMToKICAgICAgICAgICAgICAgIAllbmRfcG9zID0gcG9zaXRpb24KICAgICAgICByZXR1cm4gZW5kX3BvcyAgIAogICAgICAgIApwcmludCBmaW5kX2xhc3QoImFhYWEiLCJhIik=