#!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin


def fibo(n):
    a, b = 1, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a


print(fibo(int(stdin.readline()))) from __future__ import division, print_function from sys import stdin def fibo(n):
    a, b = 1, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a fibo a, b = 1, 1 a 1 b 1 while n:
        a, b = b, a + b
        n -= 1
     n a, b = b, a + b a b b a + b a b n -= 1 n 1 return a a n n print(fibo(int(stdin.readline()))) print fibo(int(stdin.readline())) fibo int(stdin.readline()) int stdin.readline() stdin.readline stdin readline def fibo(n):
    a, b = 1, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a def fibo(n):
    a, b = 1, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a fibo
#!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin


def fibo(n):
    a, b = 1, 1
    while n:
        a, b = b, a + b
        n -= 1
    return a


print(fibo(int(stdin.readline())))