import sys, math
from itertools import permutations, combinations
from collections import defaultdict, Counter, deque
from math import factorial#, gcd
from bisect import bisect_left #bisect_left(list, value)
sys.setrecursionlimit(10**7)
enu = enumerate
MOD = 10**9+7
def input(): return sys.stdin.readline()[:-1]
def pri(x): print('\n'.join(map(str, x)))

N = int(input())

fib = [1]*50

for i in range(N+2):
    fib[i+2] = fib[i] + fib[i+1]

print(fib[i-1])

 import sys, math sys math from itertools import permutations, combinations from collections import defaultdict, Counter, deque from math import factorial from bisect import bisect_left sys.setrecursionlimit(10**7) sys.setrecursionlimit sys setrecursionlimit 10**7 10 7 enu = enumerate enu enumerate MOD = 10**9+7 MOD 10**9+7 10**9 10 9 7 def input(): return sys.stdin.readline()[:-1] input def pri(x): print('\n'.join(map(str, x))) pri x x N = int(input()) N int(input()) int input() input fib = [1]*50 fib [1]*50 [1] 1 50 for i in range(N+2):
    fib[i+2] = fib[i] + fib[i+1] i range(N+2) range N+2 N 2 fib[i+2] = fib[i] + fib[i+1] fib[i+2] fib i+2 i 2 fib[i] + fib[i+1] fib[i] fib i fib[i+1] fib i+1 i 1 print(fib[i-1]) print fib[i-1] fib i-1 i 1 def input(): return sys.stdin.readline()[:-1] def input(): return sys.stdin.readline()[:-1] input N = int(input()) int(input()) N enu = enumerate enumerate enu MOD = 10**9+7 10**9+7 MOD fib = [1]*50 [1]*50 fib def pri(x): print('\n'.join(map(str, x))) def pri(x): print('\n'.join(map(str, x))) pri
import sys, math
from itertools import permutations, combinations
from collections import defaultdict, Counter, deque
from math import factorial#, gcd
from bisect import bisect_left #bisect_left(list, value)
sys.setrecursionlimit(10**7)
enu = enumerate
MOD = 10**9+7
def input(): return sys.stdin.readline()[:-1]
def pri(x): print('\n'.join(map(str, x)))

N = int(input())

fib = [1]*50

for i in range(N+2):
    fib[i+2] = fib[i] + fib[i+1]

print(fib[i-1])


