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;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> P;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

const double EPS = 1e-9;
const double PI  = acos(-1.0);
const int INT_INF = 2147483647;
const long long LL_INF = 1LL<<60;
const long long MOD = 1000000007;

#define CLR(a) memset((a), 0, sizeof(a))

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

int fib[50];

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

int main(void){
    int n; cin >> n;
    REP(i,50) fib[i] = -1;
    fib[0] = 1; fib[1] = 1;
    int ans = rec(n);
    cout << ans << en;
    return 0;
}

C++: #include <iostream>

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)

const int SIZE = 45;
int f[SIZE];

int fib(int n) {
  if (f[n]) return f[n];

  if (n == 0 || n == 1) return f[n] = 1;
  return f[n] = fib(n - 1) + fib(n - 2);
}

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

  std::cout << fib(n) << '\n';
  return 0;
}

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

using namespace std;

#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define rep(i, j) FOR(i, 0, j)
#define repr(i, j) for(int i = j; i >= 0; --i)
#define INF (1 << 30)
#define MOD 1e9 + 7

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;

int dp[45];

int fib(int n) {
	if(dp[n] >= 0) return dp[n];
	else return dp[n] = fib(n - 1) + fib(n - 2);
}

int main() {
	memset(dp, -1, sizeof(dp));
	dp[0] = 1;
	dp[1] = 1;
	int n;
	scanf("%d", &n);
	printf("%d\n", fib(n));
	return 0;
}

C++: #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
template<typename T> bool chmax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<typename T> bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;}
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(vec) vec.begin(),vec.end()
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef tuple<ll,ll,ll> tlll;
typedef tuple<int,int,int> tiii;
const ll mod=1e9+7;
const int inf=1<<30;

ll dp[45];

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

C++: #include<cstdio>
#include<cmath>
#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<cstdlib>
#include<iomanip>
#include<queue>
#include<set>
#include <valarray>
#include<stack>
#include<sstream>
#include<math.h>

using namespace std;

void Solution()
{
	int n;
    cin >> n;
    
    vector<int> a;
    a.push_back(0);
    a[0]=1;
    
    a.push_back(1);
    a[1]=1;
    
    for ( int i = 2; i <= n; i++ ) 
    {
        a.push_back(i);
        a[i] = a[i-2] + a[i-1];
    }
    
    cout << a[n] << endl;
}

int main()
{
	Solution();
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int  F[45]={};
int fib(int n){
  if(n==0||n==1)return 1;
  if(F[n]!=0)return F[n];
  return F[n]=fib(n-1)+fib(n-2);
}

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