enter the string: 
ffffffa1 ffffff97 ffffff87 59 7e ffffffdf 47 ffffffa9 18 ffffffe9 ffffffff 51 52 ffffffe3 57 ffffffcd 30 ffffffa9 78 ffffff89 25 39 ffffffb8 39 ffffff86 ffffffb1 e 11 16 15 ffffffbd 61 4e 15 ffffffaf fffffff9 ffffffe0 17 ffffffdd ffffff8d 11 11 11 11 ffffff81 fffffffb ffffff82 71 6a 35 11 11 1 fffffffb ffffffda 31 12 ffffffe5 11 11 ffffffc1 15 ffffffb8 fffffff5