def fibonacci(n):
if n == 1: return 1
if n == 0: return 0
if n < 0: raise Exception('solo z+')
print(n)
return n + fibonacci(n-1)
num = int(input())
print(fibonacci(num))
ZGVmIGZpYm9uYWNjaShuKToKCWlmIG4gPT0gMTogcmV0dXJuIDEKCWlmIG4gPT0gMDogcmV0dXJuIDAKCWlmIG4gPCAwOiByYWlzZSBFeGNlcHRpb24oJ3NvbG8geisnKQoJcHJpbnQobikKCXJldHVybiBuICsgZmlib25hY2NpKG4tMSkKCQkKbnVtID0gaW50KGlucHV0KCkpCnByaW50KGZpYm9uYWNjaShudW0pKQo=