Go: package main

/*
フィボナッチ数列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func fibWithMemo(n int, memo map[int]int) int {
	if n == 0 || n == 1 {
		return 1
	}
	if val, ok := memo[n]; ok {
		return val
	}
	memo[n] = fibWithMemo(n-1, memo) + fibWithMemo(n-2, memo)
	return memo[n]
}

func fib(n int) int {
	memo := make(map[int]int)
	return fibWithMemo(n, memo)
}

func main() {
	scanner := makeScanner(1024)
	n := eGetInt(scanner)
	fmt.Println(fib(n))
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
const double PI = acos(-1);
const ll MOD = 1000000007;
using Graph = vector<vector<int>>;

int main() {
  int n; cin >> n;
  vector<ll> a(n+1);

  a[0] = a[1] = 1;

  for (int i = 2; i <= n; i++) a[i] = a[i-1] + a[i-2];

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

C++: #include <stdio.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
int f[50];

void fi(int a) {
  f[a] = f[a - 2] + f[a - 1];
}

int main(void) {
  int n;
  scanf("%d", &n);
  rep(i, 50) f[i] = 0;
  f[0] = 1, f[1] = 1;
  for(int i = 2; i < 50; ++i) fi(i);
  printf("%d\n", f[n]);
  return 0;
}

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

using namespace std;

int fib(int n) {

	if (n == 0 || n == 1)
		return 1;

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

int main() {

	int n;
	scanf("%d", &n);

	cout << fib(n) << endl;

	return 0;

}

C++: #include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); ++i)
#define outl(x) cout<< (x) << '\n'
#define fi first
#define se second
using pii = pair<int,int>;
using ll = long long;

int main()
{
   cin.tie(0), ios::sync_with_stdio(false);
   ll fib[45] = {1, 1};

   int n;
   cin >> n;
   for (int i=2; i <= n; ++i) {
       fib[i] = fib[i-1] + fib[i-2];
   }

   outl(fib[n]);
}

C++: #include <bits/stdc++.h>

//#include <vector>
#define ALL(l)  (l).begin(),(l).end()
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using namespace std;
typedef long long ll;
ll mod = 1000000007;
ll maxn = 1000000000;

//---------------------------------------------------------------------------------------------------
using vi = vector<int>; // intの1次元の型に vi という別名をつける
using vvi = vector<vi>; // intの2次元の型に vvi という別名をつける
using vs = vector<string>; // stringの1次元の型に vs という別名をつける
using pii = pair<int, int>; // これ以降 pii という型名はpair<int, int> と同じ意味で使える
//---------------------------------------------------------------------------------------------------


 
int main(){
 
   
    ll n,ans;
    cin>>n;
       vi s(n+1);
        s.at(0)=1;
    s.at(1)=1;
    
    for(int i=2;i<=n;i++){
        s.at(i)=s.at(i-1)+s.at(i-2);
    }
    
    
    
    cout<<s.at(n)<<endl;
}

C++: #include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);
    int F[50];
    F[0] = 1;
    F[1] = 1;
    for(int i=2; i<50; i++) F[i] = F[i-2] + F[i-1];
    
    printf("%d\n", F[n]);
    return 0;
}

C++: #include <iostream>
#define MAX 45
using namespace std;

int main() {
  int dp[MAX];
  dp[0] = dp[1] = 1;
  for (int i = 2; i < MAX; i++) {
    dp[i] = dp[i - 1] + dp[i - 2];
  }

  int n;
  cin >> n;
  cout << dp[n] << endl;

  return 0;
}

C++: #include <iostream>

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

C++: #include<iostream>
#include<algorithm>
#include<stdlib.h>
#include<cstdio>
int fib(int);
using namespace std;
int main()
{
	int n,ans,dp[1001];
	dp[0] = 1;
	dp[1] = 1;
	cin >> n;
	for (int i = 0; i <= n; i++){
		dp[i + 2] = dp[i] + dp[i + 1];
	}
	//ans = fib(n - 1);
	ans = dp[n];
	cout << ans << endl;
}
int fib(int n)
{
	if (n < 1)
		return 1;
	else
	{
		return fib(n - 1)+fib(n - 2);
	}
}

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

// コンテスト中のみ
//#define int long long

#define ll long long
#define rep(i,n) for(int i = 0; i < (n); i++)
#define P pair<ll,ll>
int MOD = 1000000007;
const ll INF = 1LL << 60;

int n;
ll fib[45];
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> n;
	fib[0] = 1; fib[1] = 1;
	for (int i = 2; i <= 44; i++) {
		fib[i] = fib[i - 1] + fib[i - 2];
	}
	cout << fib[n] << endl;
	return 0;
}