Go: package main

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

// func fib(n int) int{
// 	if n == 0 || n == 1{
// 		return 1
// 	} else {
// 		return fib(n-1) + fib(n-2)
// 	}
// }

// func main(){
// 	sc := bufio.NewScanner(os.Stdin)
// 	sc.Scan()
// 	n, _ := strconv.Atoi(sc.Text())
// 	fmt.Println(fib(n))
// }

import (
	"fmt"
)

func main(){
	var n, pre1, pre2, now int
	fmt.Scan(&n)
	if n == 0 || n == 1{
		fmt.Println(1)
	} else {
		pre1, pre2 = 1, 1
		for i:=1; i<n; i++{
			now = pre1 + pre2
			pre2 = pre1
			pre1 = now
		}
		fmt.Println(now)
	}

}

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

using namespace std;

#define rep(i, n) for (int i = 0; i < n; ++i)


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

    int fib[50];
    fib[0] = 1;
    fib[1] = 1;

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


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

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

C++: #include<iostream>
#include<vector>
#include<limits.h>
using namespace std;

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

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	int n;
	cin >> n;
	
	cout << Fib(n)<<endl;
	return 0;
}

C++: #include <iostream>

using namespace std;

int A[128]
int fib(int n){
  A[0] =1
  for(int i=1;i<n;++i){
    A[i] =A[i-1];
    if(i>2)A[i]+=A[i-2];
    if(i>3)A[i]+=A[i-3];
  }
  return A[n-1];

}

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

C++: #include <iostream>
#define MAX 44
using namespace std;

long long fib[MAX];

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

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
const double pi = acos(-1);
#define FOR(i,a,b) for (ll i=(a),__last_##i=(b);i<__last_##i;i++)
#define RFOR(i,a,b) for (ll i=(b)-1,__last_##i=(a);i>=__last_##i;i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define __GET_MACRO3(_1, _2, _3, NAME, ...) NAME
#define rep(...) __GET_MACRO3(__VA_ARGS__, FOR, REP)(__VA_ARGS__)
#define rrep(...) __GET_MACRO3(__VA_ARGS__, RFOR, RREP)(__VA_ARGS__)
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
REP(i,v.size()){if(i)os<<" ";os<<v[i];}return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
REP(i,v.size()){if(i)os<<endl;os<<v[i];}return os;}

int main() {
    // Write Your Code Below
    int n; cin >> n;
    vector<ll> 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;

}

C++: #include <cstdio>
#define REP(I,n) for(int i=2;i<=n;i++)
using namespace std;
int main(){
  int n;
  int F[45]={0};
  scanf("%d",&n);
  F[0]=F[1]=1;
  REP(i,n) F[i]=F[i-1]+F[i-2];
  printf("%d\n",F[n]);
  return 0;
}

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

const char wall = '#';
vector<vector<char>> fields;
vector<vector<bool>> used;
vector<vector<ll>> dist;
const int dx[4] = {0, -1, 0, 1};
const int dy[4] = {1, 0, -1, 0};

ll N;
vector<ll> F(44, 0);

ll gcd(ll a, ll b) { return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) { return b/gcd(a,b)*b;}

void fibo(ll n) {
  if (n == 0) F[0] = 1;
  else if (n == 1) F[1] = 1;
  else F[n] = F[n-1] + F[n-2];
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> N;
  rep(i, N) {
    fibo(i);
  }
  if(N < 2) cout << 1 << endl;
  else cout << F[N-1]+F[N-2] << endl;
  return 0;
}

C++: #include<cstdio>

int main(){
    int a[44],n;
    a[0]=a[1]=1;
    for(int i=2;i<=44;i++) a[i]=a[i-1]+a[i-2];
    scanf("%d",&n);
    printf("%d\n",n);
    return 0;
}

C++: #include<bits/stdc++.h>
#define int long long
using namespace std;
 
signed main(){
	vector<int>a(45);
	a[0]=a[1]=1;
	for(int b=2;b<45;b++)a[b]=a[b-1]+a[b-2];
	int c;
	cin>>c;
	cout<<a[c]<<endl;
}

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++: #include <bits/stdc++.h>

using namespace std;

#define FOR(i,s,e) for((i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)

#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))

typedef long long ll;
typedef pair<int, int> PII;

const double EPS = 1e-10;

const int N = 44;
int n;
int memo[N+1];

//?????????TLE?§£???
//?¨?????????????????????§2^44 - (?????????)

int fib(int k) {
  if (memo[k]) return memo[k];
  return fib(k-1) + fib(k-2);
}

int dp(int k) {
  memset(memo, 0, sizeof(memo));
  if (k<=1) return 1;
  memo[0] = memo[1] = 1;
  for (int i=2; i<=k; i++)
    memo[i] = memo[i-1] + memo[i-2];
  return memo[k];
}

int main() {
//  memset(memo, 0, sizeof(memo));
//  memo[0] = memo[1] = 1;
  scanf("%d ", &n);
//  printf("%d\n", fib(n));
  printf("%d\n", dp(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){
  int memo[1000] = {0};
  if(n==0 || n == 1){
    return 1;
  }else if(memo[n] != 0){
    return memo[n];
  }else{
    return memo[n] = memo[n-1] + memo[n-2];
  }
}

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

const int MAX = 44;
int F[MAX];

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


int main() {
    ios::sync_with_stdio(false);

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

    int n;
    cin >> n;
    cout << fib(n) << endl;
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define ll long long
ll fib(ll  n)
{
  ll f[100000];
  ll i;
  f[0] = 1;
  f[1] = 1;
  for (i = 2; i <= n; i++)
      f[i] = f[i-1] + f[i-2];

  return f[n];
}
int main(){
    ll i,j,k,l,n,m;
    cin>>m;
    cout<<fib(m)<<endl;
    return 0;
}

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

using namespace std;

int main(){
    int n;
    scanf("%d", &n);

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

C++: #include <bits/stdc++.h>
#include <cmath>

using namespace std;
#define rep(i, n) for (ll i = 0; i < (n); ++i)
//#define rep(i, n) for (int i = 0; i < (n); ++i)
#define sz(x) ll(x.size())
//typedef long long ll;
typedef long long ll;
//typedef pair<int, int> P;
//typedef pair<ll, ll> P;
//const double INF = 1e10;
const ll INF = 10e15;
const ll MINF = -10e10;
//const int INF = INT_MAX / 100;
#define cmin(x, y) x = min(x, y)
#define cmax(x, y) x = max(x, y)


//ifstream myfile("~/Downloads/02.txt");
//ofstream outfile("log.txt");
//outfile << setw(6) << setfill('0') << prefecture << setw(6) << setfill('0') << rank << endl;
// std::cout << std::bitset<8>(9);

//typedef priority_queue<P, vector<P>, greater<P> > PQ_ASK;
const int mod = 1000000007;
const double PI = 3.14159265358979323846;

typedef pair<string, int> P;


string to_upper(string str) {
    int diff = 'a' - 'A';
    for (int i = 0; i < str.size(); i++) {
        char c = str[i];
        if ('A' <= c && c <= 'Z') {
            c += diff;
            str[i] = c;
        }
    }
    return str;
}


int main() {
    vector<ll> fibonacci(50, 0);
    fibonacci[0] = 1;
    fibonacci[1] = 1;
    for (int i = 2; i < 50; i++) {
        fibonacci[i] = fibonacci[i - 1] + fibonacci[i - 2];
    }

    int n;
    cin >> n;
    cout << fibonacci[n] << endl;

}