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: #!/usr/bin/env python3
# -*- coding: utf-8 -*-

import sys
import re
import math
import itertools
import functools
import logging

logging.basicConfig(level=logging.DEBUG, format="DBG: %(message)s")

def dbg(msg, *args, **kwargs):
    logging.debug(msg, *args, **kwargs)

def fib(n):
    assert n >= 0

    f0 = 1
    f1 = 1

    if n == 0: return f0
    if n == 1: return f1

    for _ in range(n-1):
        f2 = f1 + f0
        f0 = f1
        f1 = f2

    return f2

def main():
    n = int(input())

    print(fib(n))

if __name__ == "__main__": main()

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys


def fib_1(n):
    if not n or n == 1:
        return 1
    return fib_1(n - 2) + fib_1(n - 1)


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    index = int(_input[0])
    print(fib_1(index))

Python: def fibonacci_dp(n,lf):
    if n == 0 or n == 1:
        return lf[n]
    if n < len(lf):
        return lf[n]
    lf.insert(n,fibonacci_dp(n-2,lf) + fibonacci_dp(n-1,lf))
    return lf[n]

if __name__ == "__main__":
    n = int(input())
    lf = [1,1,]
    print(fibonacci_dp(n,lf))

Python: def make_fibonacchi(n: int):
    
    res = {}
    
    res[0] = 1
    res[1] = 1
    
    if n == 0 or n == 1:
        return 1
    
    for i in range(2, n + 1):
        res[i] = res[i-1] + res[i-2]
    
    return res[n]


n = int(input())
print(make_fibonacchi(n))

Python: n = int(input())

A = []
A.append(1)
A.append(1)

if n>1:
    for i in range(n-1):
        A.append(A[i]+A[i+1])

print(A[n])

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

first = 1
second = 1
for i in range(n):
    second, first = first + second, second
print(val)

Python: n = int(input())
n1 = 1
n2 = 1
result = 0
if n < 2:
    result = 1
else:
    for i in range(n-1):
        result = n1 + n2
        n2 = n1
        n1 = result
print(result)

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

Python: N = int(input())
A = [0]*(N+1)
if N == 0 or N == 1:
    print(1)
else:
    A[0] = 1
    A[1] = 1
    for i in range(2, N+1):
        A[i] = A[i-1] + A[i-2]
    print(A[N])

Python: 


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

def fibonacci(n):
    if n == 0 or n == 1: return 1
    else: return(fibonacci(n-1)+fibonacci(n-2))

n = int(input())
F = [-1 for i in range(50)]
F[0] = F[1] = 1   #n=0 t0 1 pre-registered
print(make_fib(n))

Python: class fibNum():
    def __init__(self):
        self.arr = [1, 1]
    def fib(self, n):
        return_num = 1
        if n > 1:
            if len(self.arr) <= n:
                self.arr.append( self.fib(n-1) + self.fib(n-2) )
            return_num = self.arr[n]
        return return_num

def main():
    n = int( input() )
    fn = fibNum()
    print( fn.fib(n) )

if __name__ == '__main__':
    main()

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[-1])

Python: n = int(input())

dp = [0]*(45)
dp[0] = 1
dp[1] = 1
def fib(i):
    j = 2
    while j <= i:
        if j >= 2:
            dp[j] = dp[j-1] + dp[j-2]
        j += 1

fib(n)
print(dp[n])

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

Python: #coding:utf-8
#1_10_A
def fibo(n, numbers):
    if n == 0 or n == 1:
        numbers[n] = 1
        return numbers[n]
    elif numbers[n]:
        return numbers[n]
    else:
        numbers[n] = fibo(n - 1, numbers) + fibo(n - 2, numbers)
        return numbers[n]

n = int(input())
fibonacci_numbers = [0 for i in range(n + 1)]
print(fibo(n, fibonacci_numbers))

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

Python: #40 フィボナッチ数列 - Time Limit Exceeded

n = int(input())
a = 1
b = 1
c = []
c.append(a)     #リストcの最後にaの値を付加
c.append(b)     #リストcの最後にbの値を付加
       
for i in range(n):
        c.append(a+b)   #リストcの最後にa+bの値を付加
        d = b           
        b += a
        a = d
print(c[n])

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

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

print(fib[n])

Python: F_list = [1,1] + [None]*43

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


n = int(input())

print(fibo(n))

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

Python: n=int(input())

a=[1]*45


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

Python: # -*- coding: utf-8 -*-
 
 
def main(n):
    lst = [1, 1]
    for i in range(2, n + 1):
        lst.append(lst[i - 2] + lst[i - 1])
    return lst[n]
 

if __name__ == '__main__': 
    n = int(input())
    print(main(n))

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

Python: n=int(input())
s=[-1 for i in range(n+1)]

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

print(fib(n))

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


if __name__ == '__main__':
    main()

Python: def g(a,b,n):
    if n==1:return a
    else:return g(a+b,a,n-1)
a,b=1,1
print(g(a,b,int(input())))

Python: n=int(input())
a,b=1,1
if n<=1:
    print(1)
else:
    for i in range(n-1):
        c=a+b
        a=b
        b=c
    print(c)

Python: def Fibonacci(n, a1, a2):
	if n<1 : return a1
	return Fibonacci(n-1,a1+a2,a1)

print( Fibonacci( int(input()), 1, 0 ) )

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

Python: n = int(input())

fib = [0]*(n+1)

for i in range(n+1):
    if i==0 or i==1:
        fib[i] = 1
    else:
        fib[i] = fib[i-1] + fib[i-2]

print(fib[n])

Python: n = int(input())
x, y = 1, 1
for i in range(n):
  x, y = y, x + y
print(x)

Python: n=int(input())
F=[None for i in range(n+1)]
F[0],F[1]=1,1
for i in range(2,n+1):
    F[i]=F[i-2]+F[i-1]

answer=F[n]
print(answer)

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

Python: num = int(input())

dp = { 0: 1, 1: 1 }
def fibonacci(n):
  return dp[n] if n in dp else fibonacci(n - 1) + fibonacci(n - 2)

print(fibonacci(num))

Python: # import bisect
# from collections import Counter, deque
# import copy
# from fractions import gcd

def resolve():
    N=int(input())

    # dp[i]はh[i]までにかかるコストの最小値
    dp = [float('inf') for _ in range(N+1)]
    dp[0] = 1
    dp[1]=1


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



resolve()