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++: 
 // C
 #ifndef _GLIBCXX_NO_ASSERT
 #include <cassert>
 #endif
 #include <cctype>
 #include <cerrno>
 #include <cfloat>
 #include <ciso646>
 #include <climits>
 #include <clocale>
 #include <cmath>
 #include <csetjmp>
 #include <csignal>
 #include <cstdarg>
 #include <cstddef>
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <ctime> 
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 #include <ccomplex>
 #include <cfenv>
 #include <cinttypes>
 #include <cstdbool>
 #include <cstdint>
 #include <ctgmath>
 #include <cwchar>
 #include <cwctype>
 #endif
 
 // C++
 #include <algorithm>
 #include <bitset>
 #include <complex>
 #include <deque>
 #include <exception>
 #include <fstream>
 #include <functional>
 #include <iomanip>
 #include <ios>
 #include <iosfwd>
 #include <iostream>
 #include <istream>
 #include <iterator>
 #include <limits>
 #include <list>
 #include <locale>
 #include <map>
 #include <memory>
 #include <new>
 #include <numeric>
 #include <ostream>
 #include <queue>
 #include <set>
 #include <sstream>
 #include <stack>
 #include <stdexcept>
 #include <streambuf>
 #include <string>
 #include <typeinfo>
 #include <utility>
 #include <valarray>
 #include <vector> 
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 #include <array>
 #include <atomic>
 #include <chrono>
 #include <condition_variable>
 #include <forward_list>
 #include <future>
 #include <initializer_list>
 #include <mutex>
 #include <random>
 #include <ratio>
 #include <regex>
 #include <system_error>
 #include <thread>
 #include <tuple>
 #include <typeindex>
 #include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #endif
using namespace std;
int dp[50];

int main(){
    int n; cin >> n;
    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;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int F[114]={};
int fib(int n){
    if(n == 0 || n == 1) return 1;
    else if(F[n] != 0) return F[n];
    else {
        return F[n] = fib(n-1) + fib(n-2);
    }
}

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >>n;
    fib(n);
    cout << F[n] << endl;
    return 0;
}

C++: #include <iostream>

using namespace std;

int main(void){
  int n;
  cin>>n;
  int A[50];
  for(int i=0;i<50;i++){
    A[i]=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>
#define rep(i,a,b) for(int i=a;i<(b);i++)
#define erep(i,a,b) for(int i=a;i<=(int)(b);i++)
#define per(i,a,b) for(int i=(b)-1;i>(a);i--)
#define eper(i,a,b) for(int i=((int)(a));i>=b;i--)
#define pb push_back
#define mp make_pair
#define INF (1<<30)-1
#define MOD 1000000007
using namespace std;
typedef long long ll;
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int gcd(int a,int b){return b?gcd(b,a%b):a;}

int n, dp[1000];
int main() {
 ios::sync_with_stdio ( false );
 cin.tie ( 0 );
    cin >> n;
    dp[0] = dp[1] = 1;
    erep(i, 2, n) { dp[i] = dp[i - 1] + dp[i - 2]; }
    cout << dp[n] << endl;
    return 0;
}

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

long long F[100000] = {};
long long f(int);

int main(){
	int n;
	cin >> n;
	cout << f(n) << endl;
	//for(int i = 0;i<n;i++) cerr << f(i) << " ";
	//cerr << endl;
	return 0;
}

long long f(int k){
	if(F[k] != 0) return F[k];
	else if (k <= 1) return F[k] = 1;
	else{
		return F[k] = f(k-1) + f(k-2);
	}
}

C++: #include <iostream>
#include <cmath>
#include <iomanip>
#include <limits>
#include <string>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
#include <map>
#include <list>
#include <cctype>
using namespace std;
typedef long long ll;
#define rep(i,n) for(ll i=0;i<(n);i++)

int main(){
    ll dp[50];
    dp[0]=1;
    dp[1]=1;
    for(int i=2;i<=44;i++){
        dp[i]=dp[i-1]+dp[i-2];
    }
    ll n;
    cin >> n;
    cout << dp[n] << endl;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,a) for(int i=0;i<a;i++)
#define pd(a,n) for(int i=0;i<n;i++)cout<<a[i]<<((i==n-1)?"\n":" ");cout<<endl;
#define pdd(a,n,m)for(int i=0;i<n;i++){for(int j=0;j<m;j++)cout<<a[i][j]<<" ";cout<<endl;}
#define mp make_pair
#define pb push_back
#define ll long long
//#define __int64 lng long
#define P pair<int,int>
#define PP pair<P,int>

int n;
int dp[1111];

int main(){
  dp[1]=1,dp[2]=2;
  cin>>n;
  for(int i=3;i<=n;i++)dp[i]=dp[i-1]+dp[i-2];
  cout<<dp[n]<<endl;
  
  return 0;
}

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

int fibo(int x) {
  int a;
  if ( x == 0 ) return 1;
  if ( x == 1 ) return 1;
  a = fibo(x-1) + fibo(x-2);
  return a;
}

int main() {
  int x, y;

  cin >> x;

  y = fibo(x);

  cout << y << endl;

  return 0;
}

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);
  }
}