def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1)
a,b=1,1
print(g(a,b,int(input()))) def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1) g if n==1:return a
    else:return g(a+b,a,n-1) n==1 n 1 a a b b n n a,b=1,1 a 1 b 1 print(g(a,b,int(input()))) print g(a,b,int(input())) g a b int(input()) int input() input a,b=1,1 1 a def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1) def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1) g b=1,1 1 b
def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1)
a,b=1,1
print(g(a,b,int(input())))