1strlen("")=0 2strlen("a")=1 3strlen("ab")=2 4strlen("abc")=3 5strlen("abcd")=4 6strlen("abcde")=5 7strlen("abcdef")=6 8strlen("abcdefg")=7 9strlen("abcdefgh")=8 10strlen("abcdefghi")=9 11strlen("abcdefghij")=10 12strlen("abcdefghijk")=11 13strlen("abcdefghijkl")=12 14strlen("abcdefghijklm")=13 15strlen("abcdefghijklmn")=14 16strlen("abcdefghijklmno")=15 17strlen("abcdefghijklmnop")=16 18strlen("abcdefghijklmnopq")=17 19strlen("abcdefghijklmnopqr")=18 20strlen("abcdefghijklmnopqrs")=19 21strlen("abcdefghijklmnopqrst")=20 22strlen("abcdefghijklmnopqrstu")=21 23strlen("abcdefghijklmnopqrstuv")=22 24strlen("abcdefghijklmnopqrstuvw")=23 25strlen("abcdefghijklmnopqrstuwvx")=24 26strlen("abcdefghijklmnopqrstuwvxy")=25 27strlen("abcdefghijklmnopqrstuwvxyz")=26 28strlen("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")=255 29strlen("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")=256 30