Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	dp := make([]int, N+1)
	dp[0] = 1
	dp[1] = 1
	for i := 2; i <= N; i++ {
		dp[i] = dp[i-1] + dp[i-2]
	}

	fmt.Fprintln(wtr, dp[N])
	wtr.Flush()
}

C++: #include <iostream>
using namespace std;

#define MAX_N 44

struct memo{
    int num;
    bool flg=false;
}Memo[MAX_N+1];

int n;
int fib(int);

int main()
{
    cin >> n;
    cout << fib(n);
    return 0;
}

int fib(int n){
    if(n == 0){
        if(!Memo[0].flg){
        Memo[0].num=1;
        Memo[0].flg=true;
        }
        return 1;
    }
    if(n == 1){
        if(!Memo[1].flg){
        Memo[1].num=2;
        Memo[1].flg=true;
        }
        return 1;
    }

    if(Memo[n].flg){
        return Memo[n].num;
    }
    else{
        Memo[n].num=fib(n-1) + fib(n-2);
        Memo[n].flg=false;
        return fib(n-1) + fib(n-2);
    }
}

C++: #include<iostream>
using namespace std;
int main(){
	const int MAX=46;
	long long f[MAX]={1,1};
	for(int i=2;i<MAX;i++)f[i]=f[i-1]+f[i-2];
	int n;
	cin>>n;
	cout<<f[n]<<endl;
	return 0;
}

C++: #define scanf_s scanf
#include <iostream>
using namespace std;
int fib(int n) 
{
	if (n >= 0) {
		if (n <= 1) return 1;
		return fib(n - 1) + fib(n - 2);
	}
}
int main(void)
{
	int n;
	scanf_s("%d", &n);
	printf("%d", fib(n));
}

C++: #define scanf_s scanf
#include <iostream>
using namespace std;
int fib(int n) 
{
	if (n >= 0) {
		if (n <= 1) return 1;
		return fib(n - 1) + fib(n - 2);
	}
}
int main(void)
{
	int n;
	scanf_s("%d", &n);
	printf("%d", fib(n));
}

C++: #include <cstdint>

using namespace std;

#define MEMO_SIZE 44
int64_t memo[MEMO_SIZE];

void fib_init()
{
  for (uint32_t i = 0; i < MEMO_SIZE; i++) {
    memo[i] = -1;
  }
}

uint32_t fib(uint32_t i)
{
  if (i == 0) {
    return 1;
  } else if (i == 1) {
    return 1;
  } else {
    int64_t val1 = memo[i - 1], val2 = memo[i - 2];
    if (val1 == -1) {
      val1 = memo[i - 1] = fib(i - 1);
    }

    if (val2 == -1) {
      val2 = memo[i - 2] = fib(i - 2);
    }

    return val1 + val2;
  }
}

#include <iostream>

int32_t main()
{
  uint32_t i;
  cin >> i;
  cout << fib(i) << endl;
  return 0;
}

C++: #include <iostream>

using namespace std;

int fib(int n);

int main() {
    int n;
    int dp[45];

    //?????????
    /* ??????3-1 */
    dp[0] = 1;
    /* ??????3-2 */
    dp[1] = 1;

    //??\???
    cin >> n;

    //DP
    for (int i = 2; i <= n; i++) {
        /* ??????3-3 */
        dp[i] = dp [i-1] + dp[i-2];
    }

    //??????
    cout << dp[n] << endl;

    return 0;
}

C++: #include <iostream>
using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int fib[45]={1,1};
    int n;
    cin>>n;
    for(int i=2; i<=n; i++) fib[i]=fib[i-1]+fib[i-2];
    cout<<fib[n]<<'\n';
    return 0;
}

C++: #include <bits/stdc++.h>
 
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(a) (a).begin(),(a).end()
 
using namespace std;
using ll  = long long;
using pll = pair<ll, ll>;
 
const ll MOD  = 1e9+7;
const ll LINF = 1LL << 60;
const int INF = 1e9 + 7;

int main(){
    int n;
    cin >> n;

    int dp[50];

    rep(i, n+1){
        if(i == 0 || i == 1)dp[i] = 1;
        else dp[i] = dp[i-1] + dp[i-2];
    }

    cout << dp[n] << endl;
}

C++: #include<iostream>
#include<vector>
using namespace std;

int main(void){
	int n;
	cin>>n;
	if(n == 0 || n == 1){
		cout<<1<<endl;
	}else{
		vector<int> v(n);
		v[0] = v[1] = 1;
		for(int i = 2 ; i <= n ; i ++){
			v[i] = v[i-1] + v[i-2];
		}
		cout<<v[n]<<endl;
	}
}

C++: #include <stdlib.h>
#include <stdio.h>

int fib(int n){
int i;
int a[25];
a[0]=a[1]=1;
for(i=2;i<=n;i++){
a[i]=a[i-1]+a[i-2];
   }
return a[n];
}

int main(){

int x,n;
scanf("%d",&n);
x=fib(n);
printf("%d\n",x);

return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string>
#include <cmath>
#include<math.h>
#include<bitset>
using namespace std;

int memo[50] = { 0 };
int fib(int n) {
	if (n == 0 || n == 1)return 1;
	else if (memo[n - 1] != 0 && memo[n - 2] != 0) {}
	else if (memo[n - 1] != 0)memo[n - 2] = fib(n - 2);
	else {
		memo[n - 1] = fib(n - 1); memo[n - 2] = fib(n - 2);
	}
	return memo[n - 1] + memo[n - 2];
}

int main() {
	int n; cin >> n;
	cout << fib(n) << endl;
}

C++: #pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define rep(i, m, n) for(int i = m; i < (n); i++)
#define print(x) cout << (x) << endl;
#define printa(x,n) for(int i = 0; i < n; i++){ cout << (x[i]) << " ";} cout << endl;
#define printa2(x,m,n) for(int i = 0; i < m; i++){ for(int j = 0; j < n; j++){ cout << x[i][j] << " ";} cout << endl;}
#define printp(x,n) for(int i = 0; i < n; i++){ cout << "(" << x[i].first << ", " << x[i].second << ") "; } cout << endl;
#define INF (1e18)
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;

int main() {
    int dp[45];
    dp[0] = 1;
    dp[1] = 1;
    int n;
    cin >> n;
    for(int i=2;i<=44;i++){
        dp[i] = dp[i-1] + dp[i-2];
    }
    cout << dp[n] << endl;


}

C++: #include<iostream>
#include<vector>

int main() {
	std::vector<int> v(2, 1);
	int num;

	std::cin >> num;

	while (v.size() < num + 1) {
		v.push_back((v.back()) + (v[v.size() - 2]));
	}

	std::cout << v.back() << std::endl;

	return 0;
}

C++: #include <iostream>
using namespace std;

int main(){
    int n;
    cin >> n;
    int F[50];
    F[0] = F[1] = 1;
    for (int i = 2; i <= n ; ++i) {
        F[i] = F[i-1] + F[i-2];
    }
    
    cout << F[n] << endl;
    return 0;
}

C++: #include <iostream>

using namespace std;

int fib(int);

int main(void){
    int n; cin >> n;
    cout << fib(n) << endl;

    return 0;
}

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

C++: #include<bits/stdc++.h>
using namespace std;

int main(void){

    int  n;
    cin >>n;
    int dp[n];
    dp[0] = dp[1] = 1;
    for(int i=2;i<=n;i++){
        dp[i] = dp[i-1]+dp[i-2];
    }
    cout<<dp[n]<<endl;
    return 0;
}