Go: package main

import "fmt"

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

	x, y := int64(0), int64(1)
	for i := 0; i < n; i++ {
		x, y = y, x+y
	}

	fmt.Println(x)
}

C++: #include <iostream>

using namespace std;

int fib(int n);
int memo[45];
int main() {
    int n;

    //??\???
    cin >> n;

    //??????
    cout << fib(n) << endl;

    return 0;
}

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

C++: #define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a,b) for(int i=a;i<=b;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define vi vector<int>
#define pb push_back
#define pi pair<int,int>
#define vp vector<pair<int,int> >
#define mp make_pair
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
#define MEMSET(a) memset(a,0,sizeof(a))
#define inf (1ll<<60)

using namespace std;

const int mod=1e9+7;

void run();

void init() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(12);
}

signed main(){
    init();
    run();
    return 0;
}

void run(){
    int n;
    cin>>n;
    vi f(n+1);
    f[0]=f[1]=1;
    REP(i,2,n){
        f[i]=f[i-1]+f[i-2];
    }
    cout<<f[n]<<endl;
}

C++: #include<iostream>
using namespace std;
int main(){
	int a[45];
	a[0]=0;
	a[1]=1;
	int n,i;
	cin>>n;
	if(n>=2){
		for(i=2;i<=n;i++){
			a[i]=a[i-1]+a[i-2];
		}
	}
	cout<<a[n]<<endl;
	return 0;
}

C++: #include <iostream>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

ll dp[50];

ll fib(int n) {
    if(n < 3) return n;
    if(dp[n] == 0) dp[n] = fib(n-1) + fib(n-2);
    return dp[n];
}

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

C++: #include <iostream>
using namespace std;
long long fibo(int n){
    long long fibodp[200];
        fibodp[0]=1;
        fibodp[1]=1;
        for(int i=2; i<=n; i++){
            fibodp[i]=fibodp[i-1]+fibodp[i-2];
        }
        return fibodp[n];
}
int main(void){
    int n;
    
    cin>>n;
    std::cout << fibo(n) << std::endl;
    return 0;
    
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int main(){
  int f[45];
  f[0]=f[1]=1;
  r(i,2,45)f[i]=f[i-1]+f[i-2];
  int a;cin>>a;
  cout<<f[a]<<endl;
}

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

using namespace std;

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

	long long int f[45];
	int n; cin >> n;

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

	cout << f[n] << "\n";

	return 0;
}

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

int dp[45];

int fib(int n) {
	if (dp[n] != -1)return dp[n];
	int res;

	if (n == 0 || n == 1) {
		res = 1;
	}
	else {
		res = fib(n - 1) + fib(n - 2);
	}

	dp[n] = res;
	return res;
}

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

	return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <iostream>
#include <string>
#include <map>
#include <queue>
#include <stdio.h>
#include <math.h>


using namespace std;

typedef long long ll;

typedef vector<vector<int>> vvi;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef vector<ll> vll;

typedef pair<int, int> P;

typedef queue<int> qi;
typedef queue<string> qs;


#define rep(i, n) for(int i=0; i<(n); ++i)
#define repp(i, a, b) for(int i = (a); i <= (b); i++)
#define Rep(i, n) for(int i=n; i >= 0; i--)

#define all(v) v.begin(), v.end()
//sort( all(v) )　などと使える

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

	vi fib(60, 1);
	rep(i, 50) fib[i + 2] = fib[i + 1] + fib[i];

	cout << fib[n] << endl;
}

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

int n;
int F[45];
int fibo(int i) {
    if (F[i]) {
        return F[i];
    }
    F[i] =  fibo(i - 1) + fibo(i-2);
    return F[i];
}

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

    return 0;
}

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

int main(){
   int n;cin>>n;
   int F[50];

   F[0] = F[1] = 1;
   for(int i = 2; i < 50; i++) {
      F[i] = F[i-2] + F[i-1];
   }
   cout << F[n] << endl;
   return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
using ll = long long; using ull = unsigned long long;
#define int ll
using vb = vector<bool>; using vvb = vector<vb>;
using vi = vector<int>; using vvi = vector<vi>;
using vl = vector<ll>; using vvl = vector<vl>;
using pii = pair<int,int>; using pll = pair<ll,ll>;
#define FOR(i,a,b) for(ll i = (a); i < (ll)(b); ++i)
#define REP(i,n) FOR(i,0,n)
#define RFOR(i,a,b) for(ll i = (ll)(b)-1;i >= a;--i)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(obj) (obj).begin(), (obj).end()
#define rALL(obj) (obj).rbegin(), (obj).rend()
#define eb(val) emplace_back(val)
const double PI = acos(-1);
const double EPS = 1e-10;
const ll MOD = 1e9+7;
void cioacc(){//accelerate cin/cout
  cin.tie(0);
  ios::sync_with_stdio(false);
}
pair<vl,vb> eratosthenes_sieve(ll n){
  vb is_prime(n+1,true);
  vl prime;
  is_prime[0] = false;
  is_prime[1] = false;
  FOR(i,2,sqrt(n)+1){
    if(!is_prime[i]) continue;
    for(ll j=2*i;j<=n;j+=i) is_prime[j] = false;
    prime.eb(i);
  }
  return {prime,is_prime};
}
signed main(){
  int n;
  cin >> n;
  vi fib(n+1,1);
  REP(i,n-1) fib[i+2] = fib[i+1]+fib[i];
  cout << fib[n] << endl;
}

C++: //#define		FILE_INPUT_DEFINE
#ifdef		FILE_INPUT_DEFINE
#include	<fstream>
#endif		// FILE_INPUT_DEFINE

#include	<iostream>

using namespace std;

#define		MAX			45

int main()
{
#ifdef		FILE_INPUT_DEFINE
	// input from txt
	std::ifstream in(R"(C:\Temp\input.txt)");
	std::cin.rdbuf(in.rdbuf());
#endif		// FILE_INPUT_DEFINE

	unsigned int		fib[MAX] = { 1, 1 };

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

	int		n;
	cin >> n;

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

	return 0;
}

C++: #include<iostream>

using namespace std;

int main(){

  int n;

  int n1,n2,st;

  n1=1;
  n2=1;
  st=1;

  cin >>n;

  for(int i=1;i<n;i++){
    st=n1+n1;
    n1=n2;
    n2=st;
  }
  cout <<st<<endl;

}

C++: #define _CRT_SECURE_NO_WARNINGS

#include<fstream>
#include<iostream>
#include<string>
#include<iomanip>
#include<list>
#include<math.h>
#include<stack>
#include<queue>
#include<vector>
#include<algorithm>
#include<utility>

using namespace std;

vector<int> v;
int a[20];
int m;
int n, q;

void dp(int cnt, int value)
{
	if (cnt >= n) {
		v.push_back(value);
		return;
	}
	dp(cnt + 1, value + a[cnt]);
	dp(cnt + 1, value);
}

int main(){
	
	cin >> n;
	int n_1 = 1, n_2 = 1;
	if (n < 2) {
		cout << "1" << endl;
	}
	else {
		for (int i = 2; i < n; i++) {
			n_1 += n_2;
			swap(n_1, n_2);
		}
		cout << n_1 + n_2 << endl;
	}

	return 0;
}

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

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

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
using namespace std;
const int num = 45;
int f[num];
inline int getNumber(int i) {
	if (i == 0 || i == 1)
		return 1;
	int j;
	for (j = 2; j <= i; j++) {
		f[j] = f[j - 1] + f[j - 2];
	}
	j--;
	return f[j];
}
int main() {
	int n;
	cin >> n;
	f[0] = 1;
	f[1] = 1;
	int x = getNumber(n);
	cout << x << endl;
	return 0;
}