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++: 
 // 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);
  }
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <queue>
#include <set>
#include <numeric>
#include <cmath>

using namespace std;

typedef long long int lld;

const lld mod = 1e9+7;
const lld INF = 1e9;
//const lld MAXN = 1e9;

int fib[45] = {0};

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

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

	return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
#include <inttypes.h>


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

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

unsigned long long ull[44];

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

C++: #include <stdio.h>
#define N 44

int Fib[N];

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

int main(){
  int n;

  scanf("%d",&n);
  fib(n);
  printf("%d\n",Fib[n]);

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define ALL(A) A.begin(),A.end()
#define RALL(A) A.rbegin(),A.rend()
typedef long long ll;
typedef pair<ll,ll> P;
const ll mod=1000000007;
const ll LINF=1LL<<60;
const int INF=1<<30;
vector<int> f(500);
int fib(int n){
	if((n == 1) || (n == 0)){
		return 1;
	}
	else if(f[n] != 0){
		return f[n];
	}
	else{
		f[n] = fib(n - 1) + fib(n - 2);
		return f[n];
	}
}
int main(){
	int n;cin>>n;
	cout << fib(n) << endl;
	return 0;
	
}

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

using namespace std;

int main()
{
    int n;
    cin>>n;
    vector<int> f(n+1,0);
    f[0]=1;
    f[1]=1;

    for (int i = 2; i < n+1; i++)
    {
        f[i]=f[i-1]+f[i-2];
    }
    cout<<f[n]<<endl;

    return 0;
}

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

void makeFibonacci(int fib[]){
  fib[0] = 1;
  fib[1] = 1;
  for(int i=2; i<=44; i++){
    fib[i] = fib[i-1] + fib[i-2];
  }
}

int main(){

  int fib[45];
  makeFibonacci(fib);

  int n;
  scanf("%d", &n);
  printf("%d\n", fib[n]);

  return -1;
}

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;

}