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>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <cmath>
#include <functional>
#include <fstream>
#include <cstdlib>
typedef long long ll;
const int MOD = 1e9+7;


#define REP(i, N) for (int i = 0; i < (N); i++)
#define REPP(i, a, b) for (int i = (a); i < (b); i++)
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define VSORT(c) sort((c).begin(),(c).end())
#define SZ(x) ((int)(x).size())
//vvintを作る　マクロで　 #define vvint(N,M) vector<vector<int>>

using namespace std;
vector<int> fibo(44,-1);

int fibonacci1(int n){
    if(n == 1 || n == 0){
        return fibo[n] = 1;
    }
    if(fibo[n] != -1){
        return fibo[n];    
    }
    return fibo[n] = fibonacci1(n-1) + fibonacci1(n-2);
}

int fibonacci2(int n){
    fibo[0] = 1;
    fibo[1] = 1;
    for(int i = 2; i < n+1;i++){
        fibo[i] = fibo[i-1] + fibo[i-2];
    }
    return fibo[n];
}


int main(){
    
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    // cout << fibonacci1(n) << endl;
    cout << fibonacci2(n) << endl;
    
    

    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <algorithm>
#include <cmath>
#include <ios>
#include <ctype.h>
#include <stack>
#include <istream>
#include <stdio.h>
#include <map>
#include <set>
#include <queue>
#include <unordered_map>
#include <functional>
#include <bitset>
#include <list>
#include <deque>
#include <time.h>
#include <random>
#include <iomanip>
#include <fstream>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define REP(i,a,b) for (int i = a; i < (b); ++i)
#define RREP(i,a,b) for (int i = a; i > (b); --i)
#define all(x) (x).begin(),(x).end()
#define YY cout << "Yes" << endl
#define NN cout << "No" << endl
const long long INF = 1000000007;
typedef long long ll;
using namespace std;
using Graph = vector<vector<int>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { return (a * b) / gcd(a,b); }
vector<int>dp(1000,-1);
int f(int n){
  if(dp[n]!=-1)return dp[n];
  return dp[n]=f(n-1)+f(n-2);
}
int solve(){
  int n;
  cin>>n;
  dp[0]=1;
  dp[1]=1;
  cout<<f(n)<<endl;
  return 0;
}
int main(){
  // ios::sync_with_stdio(false);cin.tie(nullptr);
  // cout << fixed;cout << setprecision(16);
  solve();
  return 0;
}

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

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

  cout << f[n] << '\n';

  return 0;
}

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

int main(void) {
    cin >> num;
    int array[num] = {};
    array[0] = 1;
    array[1] = 1;
    for (int i= 2; i <= num; i++) {
        array[i] = array[i - 1] + array[i - 2];
    }
    cout << array[num] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)

int DP[45];
void init(){
    rep(i,45)DP[i]=-1;
}

int fibonaci(int n){
    if(DP[n]!=-1)return DP[n];
    if(n==0||n==1)return DP[n]=1;
    return DP[n]=fibonaci(n-1)+fibonaci(n-2);
}

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

C++: #include<iostream>

using namespace std;
int fib(int n);
int memo[45];
int main() {
  int n;

  //入力
  cin >> n;

  //出力
  cout << fib(n) << endl;

  return 0;
}

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

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

int result[45];

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

int main(){
    int n;
    for(int i = 0;i < 45;++i){
        result[i] = -1;
    }
    cin >> n;
    cout << fib(n) << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
using namespace std;
using Graph = vector<vector<int>>;
#define MOD 1000000007
#define MOD2 998244353
#define INF ((1<<30)-1)
#define LINF (1LL<<60)
#define EPS (1e-10)
typedef long long ll;
typedef pair<ll, ll> P;


ll dp[50];

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

C++: #include <stdio.h>

//int f[44];

int fib(int n)
{
  if (n < 2) return 1;
  //if (f[n] == 0) f[n] = 
  return fib(n - 1) + fib(n - 2);
  //return f[n];
}

int main()
{
  int n;

  scanf("%d", &n);

  printf("%d\n", fib(n));

  return (0);
}

C++: #include <iostream>
#include <stdlib.h>
 
using namespace std;
 
#define MAX_N 44

class Fib{
private:
  int size;
  int *A;
public:
  Fib(int size){
    this->size = size;
    makeFib();
  }

  int getFib(int n){
    return A[n];
  }

  void makeFib(){
    int i;
    this->A = (int*)malloc(sizeof(int)*this->size);
    this->A[0] = 1;
    this->A[1] = 1;
    for(i = 2;i < this->size;i++){
      this->A[i] = this->A[i-2]+this->A[i-1];
    }
  }

  ~Fib(){
    free(A);
  }
};
 
int main(){
 
    int n;
    Fib *fib = new Fib(MAX_N); 

    cin >> n;
 
    cout << fib->getFib(n) << endl;
 
    delete fib;

    return 0;
}