import sys
import itertools
# import numpy as np
import time
import math
 
sys.setrecursionlimit(10 ** 7)
 
from collections import defaultdict
 
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N = int(input())

dp = [0] * (N + 1)
dp[0] = 1
dp[1] = 1

def fib(n):
    if dp[n] > 0:
        return dp[n]
    
    dp[n] = fib(n - 1) + fib(n - 2)
    return dp[n]

print(fib(N))
     import sys sys import itertools itertools import time time import math math sys.setrecursionlimit(10 ** 7) sys.setrecursionlimit sys setrecursionlimit 10 ** 7 10 7 from collections import defaultdict read = sys.stdin.buffer.read read sys.stdin.buffer.read sys.stdin.buffer sys.stdin sys stdin buffer read readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline readlines = sys.stdin.buffer.readlines readlines sys.stdin.buffer.readlines sys.stdin.buffer sys.stdin sys stdin buffer readlines N = int(input()) N int(input()) int input() input dp = [0] * (N + 1) dp [0] * (N + 1) [0] 0 N + 1 N 1 dp[0] = 1 dp[0] dp 0 1 dp[1] = 1 dp[1] dp 1 1 def fib(n):
    if dp[n] > 0:
        return dp[n]
    
    dp[n] = fib(n - 1) + fib(n - 2)
    return dp[n] fib if dp[n] > 0:
        return dp[n]
    
     dp[n] > 0 dp[n] dp n 0 return dp[n] dp[n] dp n dp[n] = fib(n - 1) + fib(n - 2) dp[n] dp n fib(n - 1) + fib(n - 2) fib(n - 1) fib n - 1 n 1 fib(n - 2) fib n - 2 n 2 return dp[n] dp[n] dp n n n print(fib(N)) print fib(N) fib N def fib(n):
    if dp[n] > 0:
        return dp[n]
    
    dp[n] = fib(n - 1) + fib(n - 2)
    return dp[n] def fib(n):
    if dp[n] > 0:
        return dp[n]
    
    dp[n] = fib(n - 1) + fib(n - 2)
    return dp[n] fib N = int(input()) int(input()) N dp = [0] * (N + 1) [0] * (N + 1) dp read = sys.stdin.buffer.read sys.stdin.buffer.read read readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline
import sys
import itertools
# import numpy as np
import time
import math
 
sys.setrecursionlimit(10 ** 7)
 
from collections import defaultdict
 
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N = int(input())

dp = [0] * (N + 1)
dp[0] = 1
dp[1] = 1

def fib(n):
    if dp[n] > 0:
        return dp[n]
    
    dp[n] = fib(n - 1) + fib(n - 2)
    return dp[n]

print(fib(N))
    
