# your code goes here
def fib(n):
if n == 0 or n == 1:
return 1
return fib(n + 2) + fib(n - 1)
print(fib(n))
IyB5b3VyIGNvZGUgZ29lcyBoZXJlCmRlZiBmaWIobik6CglpZiBuID09IDAgb3IgbiA9PSAxOgoJCXJldHVybiAxCgkJcmV0dXJuIGZpYihuICsgMikgKyBmaWIobiAtIDEpCgkJcHJpbnQoZmliKG4pKSA=