Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list {
		buf.Write([]byte(fmt.Sprintf(" %d", v)))
	}
	buf.Write([]byte("\n"))
	buf.Flush()
}

//solve
//単純な場合
func fibonacci_(n int) int {
	if n == 0 || n == 1 {
		return 1
	}
	return fibonacci_(n-2) + fibonacci_(n-1)
}

//メモ再帰の利用
func fibonacci(n int) int {
	if n == 0 || n == 1 {
		F[n] = 1
	}
	//F[n]が計算済みの場合
	if F[n] > 0 {
		return F[n]
	}
	F[n] = fibonacci(n-2) + fibonacci(n-1)
	return F[n]
}

const MAX = 50

var F [MAX]int

func main() {
	sc.Split(bufio.ScanWords)
	n := nextInt()
	fmt.Println(fibonacci(n))

}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(a);i<=(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(b);i>=(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
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;}

void solve(){
    ll n;cin>>n;
    vl dp(n+1);
    dp[0]=dp[1]=1;
    fore(i,2,n)dp[i]=dp[i-2]+dp[i-1];
    cout<<dp[n]<<endl;
}

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

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

C++: #include <iostream>

using namespace std;


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

}

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

C++: w#include <stdio.h>
int fib(int);
int fibo[45];
int main(){
  int n,i;
  for(i=0;i<45;i++)fibo[i]=-1;
  scanf("%d",&n);
  printf("%d\n",fib(n));
  return 0;
}
int fib(int n){
  if(n==0 || n==1)return fibo[n]=1;
  if(fibo[n]!=-1)return fibo[n];
  return fibo[n]=fib(n-1)+fib(n-2);
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef  long long ll;
using vll=vector<ll>;
using vi=vector<int>;
using vb=vector<bool>;
using pii=pair<int,int>;

template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b;return true;}return false;}
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b;return true;}return false;}

//pow(llpow,modpow)
template<class T> ll llpow(ll x,T n){ll ans=1;if(x==0)ans=0;while(n){if(n&1)ans*=x;x*=x;n>>=1;}return ans;}
long long modpow(long long a, long long n, long long mod) {long long res = 1;while (n > 0) {if (n & 1) res = res * a % mod;a = a * a % mod;n >>= 1;}return res;}
//最大公約数
template<class T> inline T gcd(T x,T y){if(y==0)return x; else {return gcd(y,x%y);}}
//最小公倍数
template<class T> inline T lcm(T x,T y){return x/gcd(x,y)*y;}
//逆元
long long modinv(long long a, long long m) {long long b = m, u = 1, v = 0;while (b) {long long t = a / b;a -= t * b; swap(a, b);u -= t * v; swap(u, v);}u %= m;if (u < 0) u += m;return u;}

#define rep(i, begin_i, end_i) for (ll i = (ll)begin_i; i < (ll)end_i; i++)

long long INF = 1LL<<60;


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

C++: #include<bits/stdc++.h>
using namespace std;
int F[45];
int f(int n){
	if(n==1||n==0)	return F[n]=1;
	if(F[n])	return F[n];
	else return F[n]=f(n-1)+f(n-2);
}
int main(){
	int n;
	cin>>n;
	cout<<f(n)<<endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define int lint
typedef long long lint;
typedef pair<int,int> P;
const int    INF=(int)1e9;
const int    MOD=(int)1e9+7;
const double EPS=(double)1e-10;
struct Accelerate_Cin{
    Accelerate_Cin(){
        cin.tie(0); ios::sync_with_stdio(0);cout<<fixed<<setprecision(20);
    };
};



signed main(){
  int n;cin>>n;
  int dp[100];

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

  cout<<dp[n]<<"\n";
  return 0;
}

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

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

C++: #include <bits/stdc++.h>
typedef long long ll;
using namespace std;
ll MOD = 1000000007;

#define vec                vector<int>
#define vecll              vector<ll>
#define vecd               vector<double>
#define vecst              vector<string>
#define vecb               vector<bool>
#define vec2(var, n, m)    vector<vector<int>> var(n, vector<int>(m, 0))
#define vecll2(var, n, m)  vector<vector<ll>> var(n, vector<ll>(m, 0))

#define rep(i,n)         for(ll i=(ll)0; i<(ll)n; i++)
#define REP(i,m,n)       for(ll i=(ll)m; i<(ll)n; i++)
#define arr(var, n)      vec var(n); rep(i,n){cin >> var[i];}
#define arrll(var, n)    vecll var(n); rep(i,n){cin >> var[i];}
#define arrst(var, n)    vecst var(n); rep(i,n){cin >> var[i];}
#define all(var)         (var).begin(), (var).end()
#define sortall(var)     sort(all(var))
#define uniqueall(v)     v.erase(unique(v.begin(), v.end()), v.end());
#define f_sum(var)       accumulate(all(var), 0)
#define f_sumll(var)     accumulate(all(var), 0LL)
#define chmin(v1, v2)    v1 = min(v1, v2)
#define chmax(v1, v2)    v1 = max(v1, v2)
#define pb(var)          push_back(var)
#define prt(var)         cout << (var) << "\n"
#define prtd(n, var)     cout << fixed << setprecision(n) << (var) << "\n"
#define prtfill(n, var)  cout << setw(n) << setfill('0') << (var);
#define prt2(v1, v2)     cout << (v1) << " " << (v2) << "\n"
#define prt3(v1, v2, v3) cout << (v1) << " " << (v2) << " " << (v3) << "\n"
#define prtall(v)        rep(i,v.size()){cout<<v[i]<<(i!=v.size()-1?" ":"\n");}
void prtok(bool ok){prt(ok ? "Yes" : "No");}
//----------------------------------------------------------------

int main(void) {
  int n;
  cin >> n;
  int dp[50];
  dp[0]=1;
  dp[1]=1;
  rep(i,47){
    dp[i+2]=dp[i+1]+dp[i];
  }
  prt(dp[n]);
}

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

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

    int fib[n+1];
    rep(i, n+1) fib[i] = 0;

    fib[0] = fib[1] = 1;
    rep(i, n+1)
    {
        if(i >= 2) fib[i] += fib[i-1] + fib[i-2];
    }
    
    cout << fib[n] << endl;
    return 0;
}

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

int main(){
    int F[44];
    F[0]=1;
    F[1]=1;
    int n;
    cin>>n;
    for(int i=2;i<=n;++i){
        F[i]=F[i-1]+F[i-2];
    }
    cout<<F[n]<<"\n";
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#define rep(i,n) for(int i=0; i<(n); ++i)
#define outl(x) cout<< (x) << '\n'
using namespace std;

int fib[45] = {1, 1};

signed main()
{
   cin.tie(0), ios::sync_with_stdio(false);
   int n;
   cin >> n;
   for(int i=2; i<=n; ++i){
      fib[i] = fib[i-1] + fib[i-2];
   }
   outl( fib[n] );
}

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];

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

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

	return 0;
}