def fib(n):
    a = 1
    b = 1
    if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c)

n = int(input())
fib(n) def fib(n):
    a = 1
    b = 1
    if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c) fib a = 1 a 1 b = 1 b 1 if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c) n == 0 n 0 print(a) print a elif n == 1:
        print(b)
     n == 1 n 1 print(b) print b for i in range(n-1):
            c = a + b
            a , b = b , c
         i range(n-1) range n-1 n 1 c = a + b c a + b a b a , b = b , c a b b c print(c) print c n n n = int(input()) n int(input()) int input() input fib(n) fib n def fib(n):
    a = 1
    b = 1
    if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c) def fib(n):
    a = 1
    b = 1
    if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c) fib n = int(input()) int(input()) n
def fib(n):
    a = 1
    b = 1
    if n == 0:
        print(a)
    elif n == 1:
        print(b)
    else:
        for i in range(n-1):
            c = a + b
            a , b = b , c
        print(c)

n = int(input())
fib(n)
