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<set>
#include<queue>
#include<algorithm>
#include<vector>

using namespace std;

int main(){

    int fib[45];
    fib[0] = 1;
    fib[1] = 1;
    int n;
    cin >> n;
    for(int i=0;i<n-1;i++){
	fib[i+2] = fib[i+1] + fib[i];
    }
    cout << fib[n] << endl;

    return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
      int dp[44]={1,1},i=2,n;
      cin >> n;
      for(;i<=n;i++)dp[i]=dp[i-1]+dp[i-2];
      cout << dp[n] << endl;
}

C++: //http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_A&lang=ja
//Fibonacci Number
#include <bits/stdc++.h>
#if LOCAL
#include "dump.hpp"
#else
#define dump(...)
#endif
using namespace std;
using ll=long long;
#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
template<class T>bool chmax(T &a, const T &b) {if (a<b) { a=b; return 1; } return 0;}
template<class T>bool chmin(T &a, const T &b) {if (b<a) { a=b; return 1; } return 0;}
int main() {
    ll n; cin>>n;
    vector<ll> dp(max(n+1,2LL));
    dp[0]=1;
    dp[1]=1;    
    FOR(i,2,n+1){
        dp[i]=dp[i-1]+dp[i-2];
    }
    cout<<dp[n]<<endl;
    return 0;
}

C++: // #include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <unordered_map>
#include <unordered_set>

using namespace std;

#define vv vector< vector< int > >
#define ll long long
#define ALL(a) (a).begin(), (a).end()
const long long mod = 1000000000 + 7;
const long long INF = 9e18;
const double PI = 3.14159265358979323846;

ll gcd(ll a, ll b){if (b == 0) return a;return gcd(b, a % b);}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

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


int main(){
    int n;
    cin >> n;
    vector<int> dp(n+1);
    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 <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <algorithm>
#include <numeric>
#include <utility>
#include <complex>
#include <functional>
#include <climits>

using namespace std;
int T[100];
int fibo(int n) {
    if(T[n] != 0) return T[n];
    T[n] = fibo(n-1) + fibo(n-2);
    return T[n];
}
int main() {
    T[0] = T[1] = 1;
    int n;
    cin >> n;
    cout << fibo(n) << endl;
}

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

int Fibonacci( int n, std::vector<int>& v ){
    if( !n || n == 1 ){
        if( !v[n] ){
            v[n] = 1;
        }
        return v[n];
    }else{
        if( !v[n] ){
            v[n] = Fibonacci( n-1, v ) + Fibonacci( n-2, v );
        }
        return v[n];
    }
}

int main(){
    int n;
    std::cin.tie(0);
    std::cin >> n;

    std::vector<int> fib(n+1, 0);
    
    std::cout << Fibonacci( n, fib ) << std::endl;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
    int n; cin >> n;
    int f[50];
    f[0] = 1;
    f[1] = 1;
    for(int i = 2; i < 50; i++) f[i] = f[i-1] + f[i-2];
    cout << f[n] << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int dx[4] = {1,0,-1,0};
int dy[4] = {0,-1,0,1};
vector<long long> ans(50,-1);
long long fib(int n){
    if(ans[n]!=-1) return ans[n];
    if(n==0 || n==1) return ans[n] = 1;
    return ans[n] = fib(n-1)+fib(n-2);
}
int main(void){
    int n;cin >> n;
    cout << fib(n) << endl;
    return 0;
}

C++: #include <stdio.h>

int fi(int a) {
  return (a == 0 || a == 1) ? 1 : fi(a - 1) + fi(a - 2);
}

int main(void) {
  int n;
  scanf("%d", &n);
  printf("%d\n", fi(n));
  return 0;
}

C++: 


/**
 *      purpose : 
 *      author  : kyomukyomupurin
 *      created : 
**/

// input/output
#include <iostream>
#include <fstream>
#include <sstream>
// container class
#include <array>
#include <deque>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>
// math, algorithm
#include <algorithm>
#include <cmath>
#include <complex>
#include <numeric>
// etc
#include <bitset>
#include <cassert>
#include <cctype>
#include <cstring>
#include <chrono>
#include <iomanip>
#include <random>
#include <utility>
// using-directive
using namespace std;
// alias template
using int64 = long long;
using vi = vector<int>;
using vl = vector<int64>;
using pii = pair<int, int>;
using pll = pair<int64, int64>;
// text macro replacement
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define print(x) cout << (x) << '\n'
#define debug(x) cerr << #x << ": " << (x) << '\n'
#define dbg(v) for (size_t _ = 0; _ < v.size(); ++_){cerr << #v << "[" << _ << "] : " << v[_] << '\n';}
// variadic template
template<typename T> inline void chmin(T &a, T b) {if (a > b) a = b; return;}
template<typename T> inline void chmax(T &a, T b) {if (a < b) a = b; return;}
// constant
const int INF = (1<<30) - 1;
const int64 INF64 = (1LL<<62) - 1;
const int MOD = 1000000007;

int64 fib[50];

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n; cin >> n;

  fib[0] = 1; fib[1] = 1;
  for (int i = 2; i < 50; ++i) {
    fib[i] = fib[i - 1] + fib[i - 2];
  }

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

  return 0;
}

C++: #include <iostream>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

ll fib(int n) {
    if(n < 2) return n;
    return fib(n-1) + fib(n-2);
}

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