enter the string: 
fffffff1 ffffffd8 ffffffe1 ffffffa2 ffffffc3 5a ffffffa9 b 7b 1d 31 ffffff85 ffffff83 44 ffffffb9 30 ffffffbf d ffffffa9 ffffffee 59 ffffff9d ffffffad ffffff9f ffffffbf 0 ffffffb1 49 7b 77 21 ffffff95 ffffff87 4b ffffffe1 32 17 4e 41 a 11 11 11 11 fffffff1 28 ffffff95 ffffffd6 65 ffffff8b 11 11 71 ffffffa4 ffffffbd 5e 55 3b 11 11 11 ffffffa4 ffffffbd ffffffe0