Go: package main

import (
	"fmt"
)

const MAX = 45

var dp [MAX]int

func fin(n int) int {
	if dp[n] != 0 {
		return dp[n]
	}

	switch n {
	case 0:
		dp[n] = 1
	case 1:
		dp[n] = 1
	default:
		dp[n] = fin(n-1) + fin(n-2)
	}
	return dp[n]
}

func main() {
	var n int
	fmt.Scan(&n)
	fmt.Println(fin(n))
}

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

using namespace std;

int fib(int n) {
    return n <= 1 ? 1 : fib(n - 1) + fib(n-2);
}

int dp[1000];

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

int fibdp(int n){
    vector<int> dpv(n);
    dpv[0] = dpv[1] = 1;
    for (int i = 2; i < n; ++i)dpv[i] = dpv[i-1] + dpv[i-2];
    return dpv[n-1];
}

int fibloop(int n){
    int fib,fib2;
    fib = fib2 = 1;
    for (int i = 2; i < n; ++i){
        int tmp = fib;
        fib = fib + fib2;
        fib2 = tmp;
    }
    return fib;
}

int main(){
    //freopen("in", "r", stdin);
    int n;
    cin >> n;
    cout << fibloop(n+1) << endl;
    return 0;
}

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

int fib(int n, int a, int b);

int main()
{
	int n;
	cin >> n;
	cout << fib(n - 1, 1, 1) << endl;
	return (0);
}


int fib(int n, int a, int b){
	int f;
	f = a;
	if (n >= 1){
		f = fib(n - 1, a + b, a);
  }
	return (f);
}

C++: #include<bits/stdc++.h>
#define N 50
using namespace std;
int n;
vector<int> data(N);


void fibo(int n){
	data.at(0) = data.at(1) = 1;
	for(int i=2;i<=n;i++) data.at(i) = data.at(i-1) + data.at(i-2);
}

int main(){
	cin >> n;
	fibo(n);
	cout << data.at(n) << endl;
}

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

int main(){

    int fib[50];
    fib[0] = fib[1] = 1;
    for(int i = 2; i <= 45; i++){
        fib[i] = fib[i - 1] + fib[i - 2];
    }

    int n; cin >> n;
    cout << fib[n] << endl;
    return 0;
}

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

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

C++: #include <iostream>
using namespace std;
#define MAX (50)
int main(void){
    unsigned long A[MAX];
    int n;
    cin>>n;
    A[0]=1;
    A[1]=1;
    for(int i=2;i<=MAX;i++)A[i]=A[i-1]+A[i-2];
    
    cout<<A[n]<<endl;
    return 0;
}

C++: #include<iostream>
using namespace std;
int n,fibonacci,f[44]={0};

int makefibnacci(int n){
  f[0]=1;
  f[1]=1;
  for(int i = 2; i <=n; i++){
    f[i]=f[i-2]+f[i-1];
  }
  return f[n];
}

int main(){
  cin >> n;
  fibonacci = makefibnacci(n);
  cout << fibonacci << endl;
  return 0;
}

C++: #include<iostream>
using namespace std;
int main(){
  int f[3]={1,1,1},n;
  cin >> n;
  while(1<n--){
    f[2]=f[0]+f[1];
    f[0]=f[1];    
    f[1]=f[2];
  }
  cout<<f[2]<<endl;
  return 0;
}

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

#define rep(i, n) for (int i=0; i<(n); ++i)
using ll = long long;
using P = pair<int, int>;

int dp[50];

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

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

  int ans = fib(n);
  cout << ans << endl;
  return 0;
}

C++: #include <bits/stdc++.h>
#ifdef _DEBUG
#include "debug.hpp"
#else
#define debug(...)
#endif
#define REP(i, m, n) for(int (i) = (m); (i) < (n); ++i)
#define rep(i, n) REP(i, 0, n)
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
const int INF = 1e9 + 7;
const ll LINF = 1LL << 60;
template<class T, class U> inline bool chmax(T &a, const U &b) { if(a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if(a > b) { a = b; return true; } return false; }

int n, dp[50];
int dfs(int i) {
  if(dp[i] >= 0) return dp[i];
  if(i == 0 || i == 1) return dp[i] = 1;
  int res = dfs(i-1) + dfs(i-2);
  return dp[i] = res;
}

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  rep(i,50) dp[i] = -1;
  cin >> n;
  cout << dfs(n) << '\n';
  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){
  /*　演習　*/
  if(n == 0) return 1;
  else if(n == 1) return 1;
  else return fib(n-1) + fib(n-2);
}

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 memo[1000]={0};

  if(n==0 || n == 1){
    return memo[n] = 1;
  }else if(memo[n] != 0){
    return memo[n];
  }else{
    return memo[n] = fib(n-1) + fib(n-2);
  }
}

C++: #include <iostream>
using namespace std;
#define MAX 45

int F[MAX];

void Fibonacci(){
  F[0] = 1; F[1] = 1;
  for( int i = 2 ; i < MAX ; i++ ) F[i] = F[i-2] + F[i-1];
}

int main(void){
  Fibonacci();
  int i;

  cin >> i;
  cout << F[i] << endl;

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#define Lens 50
using namespace std;

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

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

int fibonacci[44];

int fib(int n){
    if(fibonacci[n]!=0){
        return fibonacci[n];
    }

    if(n==0||n==1){
        fibonacci[n] = 1;
        return 1;
    }

    fibonacci[n] = fib(n-1) + fib(n-2);
    return fibonacci[n];
}

int fib2(int n){
    if(n==1 || n==0){
        return 1;
    }
    return fib2(n-1) + fib2(n-2);
}

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

C++: #include <iostream>

using namespace std;

int fib(int n)
{
  if (!n || n == 1)
    return 1;
  else
    return fib(n - 1) + fib(n - 2);
}

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

  cout << fib(n) << endl;

  return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#define FOR(i,b,e) for(int i=b;i<e;i++)
#define REP(i,n) FOR(i,0,n)
using namespace std;

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

int main() {
	cin.tie(0);
 	ios::sync_with_stdio(false);

  int n;
  cin >> n;
  int dp[n+1];
  REP(i, n+2) {
    if (i == 0 || i == 1) dp[i] = 1;
    else dp[i] = -1;
  }

  cout << fib(n, dp) << endl;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdio>
#include <vector>
#include <string>
#include <array>
#include <queue>
#include <deque>
#include <set>
#include <unordered_set>
#include <list>
#include <map>
#include <stack>
#include <utility>
#include <bitset>
#include <complex>
#include <algorithm>
#include <numeric>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <cstring>
#include <climits>
#include <random>
#include <functional>
#include <sstream>
#include <iomanip>

using namespace std;

#define rep(i, n) for(int i=0; i<(n); ++i)
#define FOR(i, m, n) for(int i=(m); i<(n); ++i)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define SORT(x) sort((x).begin(),(x).end())
#define REVE(x) reverse((x).begin(),(x).end())
#define mp make_pair
#define pb push_back
#define Cout(x) cout << (x) << endl
#define Cout2(x, y) cout << (x) << " " << (y) << endl
#define dump(x) cout << #x << " = " << (x) << endl;
#define forauto(i, a) for(auto i : a)cout << i << " "; puts("");

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef vector<string> VS;
typedef vector<bool> VB;
typedef vector<vector<int>> VVI;
typedef pair<int, int> PII;
typedef pair<double, double> PDD;
typedef complex<double> CD;

int main() {
	LL fib[47];
	fib[0] = 1;
	fib[1] = 1;
	FOR(i, 2, 45)fib[i] = fib[i - 1] + fib[i - 2];

	int n; cin >> n;
	cout << fib[n] << endl;
}