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 sys
read = sys.stdin.read
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 8)
INF = float('inf')
MOD = 10 ** 9 + 7


def main():
    N = int(readline())
    dp = [0] * 47
    dp[0] = 1
    dp[1] = 1
    for i in range(2,N+1):
        dp[i] = dp[i-1] + dp[i-2]
    print(dp[N])



if __name__ == '__main__':
    main()

Python: MAX = 10**5
fib = [0]*MAX

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

N = int(input())
print(fibonacci(N))

Python: from functools import lru_cache

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

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

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

Python: def fib(n):
    if n == 0:
        return 1
    elif n == 1:
        return 1

    return fib(n - 1) + fib(n - 2)

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

Python: n = int(input())

dp = [0 for _ in range(45)]

def fib_dp(n):
    dp[0] = 1
    dp[1] = 1
    for i in range(2, n+1):
        dp[i] = dp[i-1] + dp[i-2]
    return dp[n]
       
print(fib_dp(n))

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

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

Python: n = int(input())
from functools import lru_cache

@lru_cache(maxsize=1000)
def fibo(n):
    if n < 2:
        return 1
    return fibo(n-1) + fibo(n-2)

print(fibo(n))

Python: class Fib:
    def __init__(self):
        self.memo = {0: 1, 1: 1}
    
    def calc_fib(self, n):
        if n in self.memo.keys():
            return self.memo[n]
        
        self.memo[n] = self.calc_fib(n - 2) + self.calc_fib(n - 1)
        return self.memo[n]
    
fib = Fib()
print(fib.calc_fib(int(input())))

Python: n = int(input())
print(round((pow((1+math.sqrt(5))/2,n) - pow((1-math.sqrt(5))/2,n)) / math.sqrt(5)))

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: a=1
b=1
list=[]
n=int(input())
list.append(a)
list.append(b)
for i in range(n):
    list.append(a+b)
    c=b
    b+=a
    a=c
print(list[n])

Python: a=[0]*45

def Fib(n):
    if n == 0:
        a[0]=1
        return 1
    elif n == 1:
        a[1]=1
        return 1
    else:
        if a[n]==0:
            a[n]=Fib(n-1)+Fib(n-2)
            return a[n]
        else:
            return a[n]
    
n=int(input())
print(Fib(n))

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

n = int(input())
print(fib(n))
#n = int(input())
#print(fib(n))
#fib(44)
#for i in range(5+1):
#  print(F[i])

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

    print(F[n])

Python: from functools import lru_cache

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

n = int(input())
ans = fib(n)

print(ans)

Python: def fib(numbers, find):
    if len(numbers) < find:
        numbers.append(numbers[-1] + numbers[-2])
        fib(numbers, find)
    else:
        print(numbers)
        print(numbers[-1])


# n = 4
n = int(input())
number_list = []


if n == 0 or n == 1:
    print(1)
else:
    number_list.append(n-2)
    number_list.append(n-1)
    fib(number_list, n)

Python: import time
import sys
input = sys.stdin.readline
sys.setrecursionlimit(1000000)


# 何も考えずに書いてみたやつ これ一番早いじゃん・・・
def fib_org(n):
    if n in (0, 1):
        return 1

    count = 3
    prevprev = 1
    prev = 2
    while count <= n:
        tmp = prevprev + prev
        prevprev = prev
        prev = tmp
        count += 1

    return prev


# 教科書通りの再起のfib
def fib(n):
    if n == 0 or n == 1:
        return 1
    return fib(n - 2) + fib(n - 1)

# def fib2(n):
#     if n == 0 or n == 1:
#         return 1
#     if
#     return fib(n - 2) + fib(n - 1)


N = int(input())
F = [0 for i in range(N + 1)]


def fib_memo(n):
    if n == 0 or n == 1:
        F[n] = 1
    if F[n] != 0:
        return F[n]
    F[n] = fib_memo(n - 2) + fib_memo(n - 1)
    return F[n]


# start = time.time()
# print('case1: original fib calculator')
# print('result:{}'.format(fib_org(N)))
# elapsed_time = time.time() - start
# print("elapsed_time:{0}[sec]".format(elapsed_time))

# start = time.time()
# print('case2: base fib calculator')
# print('result:{}'.format(fib(N)))
# elapsed_time = time.time() - start
# print("elapsed_time:{0}[sec]".format(elapsed_time))

# start = time.time()
# print('case3: memo fib calculator')
# print('result:{}'.format(fib_memo(N)))
# elapsed_time = time.time() - start
# print("elapsed_time:{0}[sec]".format(elapsed_time))

# 以下提出用
print(fib_org(N))

Python: n=int(input())
num=[1,1]
for i in range(43):
    b=(num[-2])+(num[-1])
    num.append(b)
print(num[(n)])

Python: N = 44
F = [0]*(N+1)

def dynamic(n):
    if n == 0 or n == 1:
        return 1
    if F[n] != 0:
        return F[n]
    F[n] = dynamic(n - 1) + dynamic(n - 2)
    return F[n]

if __name__ == '__main__':
    n = int(raw_input())
    print(dynamic(n))

Python: def fib2(n):
    a1, a2 = 1, 0
    while n > 0:
        a1, a2 = a1 + a2, a1
        n -= 1
    return a1

Python: def make_fibonacci(n):
    F = []
    F.append(1)
    F.append(1)
    for i in range(2, n+1):
        F.append(F[i-2]+F[i-1])
    return F

n = int(input())
F = make_fibonacci(n)
print(F[n])

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

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

Python: n = int(input())
F = [1, 1] + [0 for i in range(44)]
for i in range(2, n + 1):
    fib[i] = fib[i - 1] + fib[i - 2]
print(fib[n])

Python: list=[1]*45

n=int(input())
def fib(n):
    if n==0 or n==1:
        return list[n]
    else:
        if list[n]==1:
            list[n]=fib(n-1)+fib(n-2)
            return list[n]
        else:
            return list[n]
      
print(fib(n))

Python: a=1
b=1
c=[]
n=int(input())
c.append(a)
c.append(b)
for i in range(n):
  c.append(a+b)
  d=b
  b+=a
  a=d
print(c[n])

Python: n=(int)(input())
a=1
b=1
i=0
for i in range(n-1):
    c=a+b
    a=b
    b=c
print(b)

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

Python: n = int(input())
def fib(n):
    if (n == 0 or n == 1):
        return 1
    else:
        return fib(n-1) + fib(n-2)
print(fib(n))

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

Python: N=int(input())
DP=[]
DP.append(1)
DP.append(1)
for i in range(2,N+1):
    DP.append(DP[i-1]+DP[i-2])
print(DP[N])