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 <iostream>
#include <algorithm>
#include <string>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <vector>
#include <queue>
#include <stack>
#include <cmath>
#include <map>
#include <iomanip>
#include <set>
#include <ctime>
#include <tuple>
#include <bitset>
using namespace std;

/*
sort(sp.begin(), sp.end(), [](PAIR l, PAIR r){
        return l.first<r.first || (l.first==r.first && l.second > r.second);
        });
*/

typedef long long  ll;

#define fi first
#define se second

using Graph = vector<vector<int>>;


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



    return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define _USE_MATH_DEFINES
#include <math.h>
#define rep(i,n) for(int i = 0;i < n;i++)
#define NIL = -1;

ll gcd(long long a,long long b) {
    if (a < b) swap(a,b);
    if (b == 0) return a;
    
    return gcd(b,a%b);
}

ll lcm(ll a,ll b){
    a / gcd(a,b) * b;
}
const ll mod = 1e9 + 7;

int dx[4] = {0,1,0,-1};
int dy[4] = {1,0,-1,0};

const ll INF = 1e9;
/////////////////////////////////////////////////////////////////////////////////////////

int main(){
    int n;
    cin >> n;
    int dp[50];
    dp[0] = 1;
    dp[1] = 1;

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

    cout << dp[n] << endl;

}

C++: #include<iostream>
using namespace std;
int main ()
{
	int fif[100];
	int n,i;
	fif[0]=1,fif[1]=1;
	cin >> n;
	for(i=2;i<=n;i++)
	{
		fif[i]=fif[i-2]+fif[i-1];
	}
	cout << fif[n] << endl;
	return 0;
}

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

using namespace std;
typedef long long int ll;

int dh[4] = {1,0,-1,0};
int dw[4] = {0,1,0,-1};

int main()
{
   int n;
   cin >> n;
   vector<int>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;
}

C++: #include <algorithm>
#include <cmath>
#include <functional>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
const int INT_INF = 500000000;
const long long LONG_LONG_INF = (long long)pow(10, 18);
const int MOD = pow(10, 9) + 7;
/* contest template */
int n;
long long fib[45];

int main() {
  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;
}

C++: #include<bits/stdc++.h>
using namespace std;
int fibo(int n){
  if(n==0||n==1)return 1;
  return fibo(n-1)+fibo(n-2);
}
int main(){
  int n;
  cin >> n;
  cout << fibo(n) << endl;
  return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <cmath>
#include <ctype.h>
#include <string>
#include <sstream>
#include <algorithm>
#include <cstdlib>
#include <map>
#include <queue>
#include <utility>
#include <vector>
#include <set>

using namespace std;

int main()
{
    int fib[45] = {};
    fib[0] = fib[1] = 1;

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

    return 0;
}

C++: #include <iostream>

using namespace std;

int fibo[45];

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

int main() {
	int n; cin >> n;
	fibo[0] = fibo[1] = 1;
	cout << fib(n) << endl;

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
typedef long long ll;
typedef pair<int, int> P;
ll dp[55];
int main() {
  int n;
  cin >> n;
  dp[0] = 1;
  dp[1] = 1;
  for (int i = 2; i < 50; i++) {
    dp[i] = dp[i - 1] + dp[i - 2];
  }
  cout << dp[n] << endl;
}

C++: //
//  main.cpp
//  fibonacci_number
//
//  Created by ???????????? on 2017/10/17.
//  Copyright ?? 2017 ????????????. All rights reserved.
//

#include <iostream>
#include <stdio.h>

using namespace std;

int main(int argc, const char * argv[]) {
    int n;
    scanf("%d", &n);
    int A[n];
    A[0]=A[1]=1;
    for(int i = 2; i <= n; i++ ){
        A[i] = A[i-2]+A[i-1];
    }
    cout << A[n] <<endl;;
    return 0;
}