Go: package main

// import (
// 	"fmt"
// 	"bufio"
// 	"strconv"
// 	"os"
// )

// func fib(n int) int{
// 	if n == 0 || n == 1{
// 		return 1
// 	} else {
// 		return fib(n-1) + fib(n-2)
// 	}
// }

// func main(){
// 	sc := bufio.NewScanner(os.Stdin)
// 	sc.Scan()
// 	n, _ := strconv.Atoi(sc.Text())
// 	fmt.Println(fib(n))
// }

import (
	"fmt"
)

func main(){
	var n, pre1, pre2, now int
	fmt.Scan(&n)
	if n == 0 || n == 1{
		fmt.Println(1)
	} else {
		pre1, pre2 = 1, 1
		for i:=1; i<n; i++{
			now = pre1 + pre2
			pre2 = pre1
			pre1 = now
		}
		fmt.Println(now)
	}

}

Python: import math
import copy
import sys
import fractions
# import numpy as np
# import statistics
import decimal
import heapq
import collections
import itertools
import bisect

# from operator import mul

sys.setrecursionlimit(100001)


# input = sys.stdin.readline
# sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputIntList():
    outputDataList = []
    inputData = input().split()
    outputDataList = [int(n) for n in inputData]

    return outputDataList


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n = int(input())

d = []
d.append(1)
d.append(1)
for i in range(2,n+1):
    d.append(d[i-1]+d[i-2])

print(d[n])

Python: #!/usr/bin/python

n = int(input())

def fib(n):
    l = [0] * (n+1)
    l[0] = 1
    l[1] = 1

    for i in range(2, n+1):
        l[i] = l[i-1] + l[i-2]

    return l[i]

print(fib(n))

Python: fib = [0 for i in range(45)]
fib[0] = 1
fib[1] = 1
for i in range(2, 45):
  fib[i] = fib[i - 1] + fib[i - 2]
n = int(input())
print(fib[n])

Python: def fibonacci(n, memo=None):
    if memo==None:
        memo = [None]*n
    if n<=1:
        return 1 
    else:
        if memo[n-2]==None:
            memo[n-2] = fibonacci(n-2, memo)
        if memo[n-1]==None:
            memo[n-1] = fibonacci(n-1, memo)
    return memo[n-1] + memo[n-2]

n = int(input())
print(fibonacci(n))

Python: n = int(input())
# dpテーブルの用意
dp = [-1]*(n+1)
# dpの初期値
dp[0], dp[1] = 1, 1

for i in range(2, n+1):
    dp[i] = dp[i-1]+dp[i-2]
print(dp[-1])

Python: # Dynamic Programming - Fibonacci Number
memo = [0]*45
for i in range(45):
    if i == 0 or i == 1:
        memo[i] = 1
    else:
        memo[i] = memo[i-1] + memo[i-2]
print(memo[int(input())])

Python: 

def fibonacciDP(i):
    if i == 0:
        return 1
    elif i == 1:
        return 1
    else:
        if dp[i-1] is None and dp[i-2] is None:
            dp[i-1] = fibonacciDP(i-1)
            dp[i-2] = fibonacciDP(i-2)
        elif dp[i-1] is None:
            dp[i-1] = fibonacciDP(i-1)
        elif dp[i-2] is None:
            dp[i-2] = fibonacciDP(i-2)

        return dp[i-1]+ dp[i-2]

def fibonacci(i):
    if i == 0:
        return 1
    elif i == 1:
        return 1
    else:
        return fibonacci(i-1)+fibonacci(i-2)



n = int(input())
dp = [None]*n

print(fibonacciDP(n))

Python: n = int(input())
fib = [-1] * (n+1)
fib[0], fib[1] = 1, 1

for i in range(2, n+1):
    fib[i] = fib[i-1] + fib[i-2]

print(fib[-1])

Python: n = int(input())
dp = [1] * (n+1)

for j in range(n-1):
    dp[j+2] = dp[j+1] + dp[j]
print(dp[n])

Python: n = int(input())

fib = [1]*(n+1)

for i in range(2,n+1):
    fib[i] = fib[i-1]+fib[i-2]
    
print(fib[n])

Python: def fib(n):
    x=[1,1]
    for i in range(n+1):
        y=x[i]+x[i+1]
        x.append(y)
    print(x[n])
    
a=int(input())
fib(a)

Python: c=int(input())
a,b =1,1
while c-1:
    a,b=a+b,a;c -=1
print(a)

Python: 
n=int(input())
f=[0]*45
def Fib(n):
    if n==0:
        return 1
    elif n==1:
        return 1
    else:
        if f[n]!=0:
            return f[n]
        else:
            f[n]=Fib(n-1)+Fib(n-2)
            return f[n]
print(Fib(n))

Python: import numpy as np
def f(n):
    m = np.matrix('1 1 ; 1 0') ** n
    return m.item(0)
print(f(int(input())))

Python: y=[1,1]
n=int(input())
for i in range(0,n):
    a=y[i]+y[i+1]
    y.append(a)
print(y[n])

Python: n=int(input())
n+=1
dp=[1 for i in range(n)]
for i in range(2,n):
    dp[i]=dp[i-1]+dp[i-2]
print(dp[-1])

Python: memo = {} #メモ化されないと時間がかかる
def fib(n):
  if n == 0 or n == 1:
    return 1
  # else:
  #   return fib(n-1) + fib(n-2)
  else:
    if n-1 not in memo:
      memo[n-1] =fib(n-1)
    if n-2 not in memo:
      memo[n-2] = fib(n-2)
    return memo[n-1]+memo[n-2]
print(fib(int(input())))

Python: #Fibonacci Number
#http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=jp


class fibonacci:
    def __init__(self):
        self.result: List[int] = [-1]*1000
        return 
    def calc(self,n):
        if (n == 0 or n == 1):
            self.result[n] = 1
            return 1
        if (self.result[n] != -1):
            return self.result[n]
        self.result[n-1] = self.calc(n-1) 
        self.result[n-2] = self.calc(n-2)
        return self.result[n-1] + self.result[n-2]
n = int(input())

print (fibonacci().calc(n))

Python: ####
n = int(input())
memo = [-1]*(n+10)
def fib(i):
    if i==0 or i == 1:
        return 1
    if memo[i] != -1:
        return memo[i]
    memo[i] = fib(i-1) + fib(i-2)
    return memo[i]
print(fib(n))

Python: n = int(input())
fib = []
for i in range (n+1) :
    if i <= 1 :
        fib.append(1)
    else :
        fib.append(fib[i-2]+fib[i-1])
print(fib[n])

Python: N = int(input())
dp = [None] * (N + 1)

def fib(n):
    if dp[n] != None:
        return dp[n]
    if n == 0 or n == 1:
        dp[n] = 1
    else:
        dp[n] = fib(n - 2) + fib(n - 1)
    return dp[n]

print(fib(N))

Python: from functools import lru_cache

n = int(input())


@lru_cache(maxsize=None)
def rec(n):
    if n <= 1:
        return 1
    else:
        return rec(n - 1) + rec(n - 2)


print(rec(n))

Python: dp = [None for _ in range(50)]

def fib(n):
    if n == 0 or n == 1:
        dp[n] = 1
        return dp[n]
    if dp[n] != None:
        return dp[n]
    dp[n] = fib(n-1) + fib(n-2)
    return dp[n]

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

Python: F = {}

def fib(n):
  global F
  if n < 0:
    print("error")
    exit()
  if n < 2:
    F[n] = 1
    return F[n]
  F[n] = F[n-1] + F[n-2]
  return F[n]

n = int(input())
for i in range(n+1):
  result = fib(i)
print(result)

Python: n = int(input())

fib = [1, 1]

for i in range(2, n+1):
    fib.append(fib[i - 2] + fib[i - 1])
print(fib[n])

Python: # -*- coding: utf-8 -*-
import sys
from functools import lru_cache
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
input=lambda: sys.stdin.readline().rstrip()
YesNo=lambda b: print('Yes' if b else 'No')
YESNO=lambda b: print('YES' if b else 'NO')

def main():
    @lru_cache()
    def fib(n):
        if n==0 or n==1:
            return 1
        return fib(n-1)+fib(n-2)
    print(fib(int(input())))
        

if __name__ == '__main__':
    main()

Python: n = int(input())
dp = [1] * (50)
for i in range(n):
    dp[i + 2] = dp[i + 1] + dp[i]

print(dp[n])

Python: n=int(input())
def fib(n):
    a=1
    b=1
    for _ in range(n):
        a,b=b,a+b
    return a
print(fib(n))

Python: def fib(n):
    a=[1,1]
    for i in range(2,n+1):
        a.append(a[i-2]+a[i-1])
        i+=1
    return a[-1]
    
n=int(input())
print(fib(n))

Python: a, b = 1, 1
for i in range(int(input())):
  a, b = b, a + b
print(a)

Python: n = int(input()) - 1
fib = [1, 1] + [0] * n
for i in range(2, n):
    fib[i] = fib[i-1] + fib[i-2]
print(fib[n+1])

Python: n=int(input())

L=[0]*(n+1)
L[0]=1
L[1]=1

for i in range(n-1):
	L[i+2]=L[i+1]+L[i]

print(L[n])