# -*- coding: utf_8 -*-

n = int(input()) + 1
arr = [-1] * n

arr[0] = 1
arr[1] = 1

for i in range(2, len(arr)):
    arr[i] = arr[i - 1] + arr[i - 2]

print(arr[n - 1]) n = int(input()) + 1 n int(input()) + 1 int(input()) int input() input 1 arr = [-1] * n arr [-1] * n [-1] -1 n arr[0] = 1 arr[0] arr 0 1 arr[1] = 1 arr[1] arr 1 1 for i in range(2, len(arr)):
    arr[i] = arr[i - 1] + arr[i - 2] i range(2, len(arr)) range 2 len(arr) len arr arr[i] = arr[i - 1] + arr[i - 2] arr[i] arr i arr[i - 1] + arr[i - 2] arr[i - 1] arr i - 1 i 1 arr[i - 2] arr i - 2 i 2 print(arr[n - 1]) print arr[n - 1] arr n - 1 n 1 arr = [-1] * n [-1] * n arr n = int(input()) + 1 int(input()) + 1 n
# -*- coding: utf_8 -*-

n = int(input()) + 1
arr = [-1] * n

arr[0] = 1
arr[1] = 1

for i in range(2, len(arr)):
    arr[i] = arr[i - 1] + arr[i - 2]

print(arr[n - 1])