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++: // input: aldsalds1_10_a.in
#include<iostream>
#define MAX_N 44
#define NIL -1
using namespace std;

int dp[MAX_N];

int fib(int n) {
  if(n == 0 || n == 1)
    return 1;

  if(dp[n] != NIL)
    return dp[n];

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

int main() {
  for(int i=0; i<MAX_N; i++)
    dp[i] = NIL;

  int x;
  cin >> x;

  cout << fib(x) << endl;
}

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



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

    ll fib[N+1];
    fib[0] = 1;
    fib[1] = 1;

    for (int i=2; i<=N; i++) fib[i] = fib[i-1] + fib[i-2];

    cout << fib[N] << endl;

    return 0;
}

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

long long n;
vector<long long> f;

long long calc(long long x) {
  if(f[x] != -1) return f[x];
  return f[x] = calc(x - 1) + calc(x - 2);
}

int main() {
  cin >> n;
  f.assign(n + 1, -1);
  f[0] = f[1] = 1;
  cout << calc(n) << endl;
  return 0;
}

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

C++: #include <iostream>
 
using namespace std;
 
typedef unsigned long long ull;
 
auto fib(ull const n) -> ull
{
    return ( n == 1 || n == 0 ) ? n : fib( n - 1 ) + fib( n - 2 );
}
 
int main()
{
    ull n;
    cin >> n;
    cout << fib( n ) << endl;
}

C++: #include<iostream>

using namespace std;

int fib(int n);

int main() {
  int n;

  //入力
  cin >> n;

  //出力
  cout << fib(n) << endl;

  return 0;
}

int fib(int n){
  int dp[1000];
  dp[0] = 1;
  dp[1] = 1;

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

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

int main(){
	
	int n[47];
	n[1]=1;n[2]=2;

	for(int i=3;i<=45;i++)
		n[i]=n[i-1]+n[i-2];

	cout<<n[44]<<endl;
	return 0;
}

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

#define INF 1e9
vector<int> memo;

int fib(int n){
  if(memo[n] == -INF){ memo[n] = fib(n - 1) + fib(n - 2); }
  return memo[n];
}

int main(void){
  int n;
  cin >> n;
  
  memo = vector<int>(n + 1, -INF);
  memo[0] = memo[1] = 1; 
  
  cout << fib(n) << endl;
  return 0;
}

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

constexpr ll DP_MAX = 1000000;
ll dp[DP_MAX];

int main(int argc, char **argv)
{
	ll n; cin >> n;
	memset(dp, 0, sizeof dp);
	dp[0] = dp[1] = 1;
	for (ll i = 2; i <= n; ++i)
		dp[i] = dp[i-1] + dp[i-2];
	std::cout << dp[n] << std::endl;
}

C++: #include<iostream>

using namespace std;

int fib(int n);

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

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

using namespace std;

int main(){
  int n; cin >> n;
  vector<int> fib;
  fib.push_back(0); fib.push_back(1);

  for(int i=0; i<n; i++)
    fib.push_back(fib[i]+fib[i+1]);

  cout << fib.back() << endl;

  return 0;
}

C++: #include <iostream>

using namespace std;

int memo[45];

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

int main()
{
    for (int i = 0; i < 45; ++i)
        memo[i] = -1;

    int n;
    cin >> n;
    cout << fibonacchi(n) << '\n';
}

C++: #include<stdio.h>

int main()
{
	int fib1{ 1 }, fib2{ 1 }, n;

	scanf("%d", &n);
	for (int i = 1; i < n; ++i)
	{
		int tmp = fib2;
		fib2 += fib1;
		fib1 = tmp;
	}
	printf("%d\n", fib2);
	return 0;
}