def fib():
	a,b,n=-1,1,int(raw_input("Enter position="))
	for i in range(n):
		b,a=a+b,b
	print b

if __name__=='__main__':
	fib()

f35ebfa6c3f470dfd360ba9c41494d2835a32a1a
def fib():
	a,b,n=-1,1,int(raw_input("Enter position="))
	for i in range(n):
		b,a=a+b,b
	print b

if __name__=='__main__':
	fib()
