Go: package main

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

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()
	n := nint()
	r := fibonacci(n)
	fmt.Println(r)
}

func fibonacci(n int) int{
	if n == 0 || n == 1{
		return 1
	}else{
		fiList := make([]int, n+1)
		fiList[0] = 1
		fiList[1] = 1
		for i:=2; i<n+1; i++{
			fiList[i] = fiList[i-1] + fiList[i-2]
		}
		return fiList[n]

	}

}

func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

C++: #include<iostream>
using namespace std;
int main(){
	const int MAX=46;
	long long f[MAX]={1,1};
	for(int i=2;i<MAX;i++)f[i]=f[i-1]+f[i-2];
	int n;
	cin>>n;
	cout<<f[n]<<endl;
	return 0;
}

C++: #define scanf_s scanf
#include <iostream>
using namespace std;
int fib(int n) 
{
	if (n >= 0) {
		if (n <= 1) return 1;
		return fib(n - 1) + fib(n - 2);
	}
}
int main(void)
{
	int n;
	scanf_s("%d", &n);
	printf("%d", fib(n));
}

C++: #define scanf_s scanf
#include <iostream>
using namespace std;
int fib(int n) 
{
	if (n >= 0) {
		if (n <= 1) return 1;
		return fib(n - 1) + fib(n - 2);
	}
}
int main(void)
{
	int n;
	scanf_s("%d", &n);
	printf("%d", fib(n));
}

C++: #include <cstdint>

using namespace std;

#define MEMO_SIZE 44
int64_t memo[MEMO_SIZE];

void fib_init()
{
  for (uint32_t i = 0; i < MEMO_SIZE; i++) {
    memo[i] = -1;
  }
}

uint32_t fib(uint32_t i)
{
  if (i == 0) {
    return 1;
  } else if (i == 1) {
    return 1;
  } else {
    int64_t val1 = memo[i - 1], val2 = memo[i - 2];
    if (val1 == -1) {
      val1 = memo[i - 1] = fib(i - 1);
    }

    if (val2 == -1) {
      val2 = memo[i - 2] = fib(i - 2);
    }

    return val1 + val2;
  }
}

#include <iostream>

int32_t main()
{
  uint32_t i;
  cin >> i;
  cout << fib(i) << endl;
  return 0;
}

C++: #include <iostream>

using namespace std;

int fib(int n);

int main() {
    int n;
    int dp[45];

    //?????????
    /* ??????3-1 */
    dp[0] = 1;
    /* ??????3-2 */
    dp[1] = 1;

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

    //DP
    for (int i = 2; i <= n; i++) {
        /* ??????3-3 */
        dp[i] = dp [i-1] + dp[i-2];
    }

    //??????
    cout << dp[n] << endl;

    return 0;
}

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

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int fib[45]={1,1};
    int n;
    cin>>n;
    for(int i=2; i<=n; i++) fib[i]=fib[i-1]+fib[i-2];
    cout<<fib[n]<<'\n';
    return 0;
}

C++: #include <bits/stdc++.h>
 
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(a) (a).begin(),(a).end()
 
using namespace std;
using ll  = long long;
using pll = pair<ll, ll>;
 
const ll MOD  = 1e9+7;
const ll LINF = 1LL << 60;
const int INF = 1e9 + 7;

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

    int dp[50];

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

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

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

int main(void){
	int n;
	cin>>n;
	if(n == 0 || n == 1){
		cout<<1<<endl;
	}else{
		vector<int> v(n);
		v[0] = v[1] = 1;
		for(int i = 2 ; i <= n ; i ++){
			v[i] = v[i-1] + v[i-2];
		}
		cout<<v[n]<<endl;
	}
}

C++: #include <stdlib.h>
#include <stdio.h>

int fib(int n){
int i;
int a[25];
a[0]=a[1]=1;
for(i=2;i<=n;i++){
a[i]=a[i-1]+a[i-2];
   }
return a[n];
}

int main(){

int x,n;
scanf("%d",&n);
x=fib(n);
printf("%d\n",x);

return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string>
#include <cmath>
#include<math.h>
#include<bitset>
using namespace std;

int memo[50] = { 0 };
int fib(int n) {
	if (n == 0 || n == 1)return 1;
	else if (memo[n - 1] != 0 && memo[n - 2] != 0) {}
	else if (memo[n - 1] != 0)memo[n - 2] = fib(n - 2);
	else {
		memo[n - 1] = fib(n - 1); memo[n - 2] = fib(n - 2);
	}
	return memo[n - 1] + memo[n - 2];
}

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

C++: #pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define rep(i, m, n) for(int i = m; i < (n); i++)
#define print(x) cout << (x) << endl;
#define printa(x,n) for(int i = 0; i < n; i++){ cout << (x[i]) << " ";} cout << endl;
#define printa2(x,m,n) for(int i = 0; i < m; i++){ for(int j = 0; j < n; j++){ cout << x[i][j] << " ";} cout << endl;}
#define printp(x,n) for(int i = 0; i < n; i++){ cout << "(" << x[i].first << ", " << x[i].second << ") "; } cout << endl;
#define INF (1e18)
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;

int main() {
    int dp[45];
    dp[0] = 1;
    dp[1] = 1;
    int n;
    cin >> n;
    for(int i=2;i<=44;i++){
        dp[i] = dp[i-1] + dp[i-2];
    }
    cout << dp[n] << endl;


}

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

int main() {
	std::vector<int> v(2, 1);
	int num;

	std::cin >> num;

	while (v.size() < num + 1) {
		v.push_back((v.back()) + (v[v.size() - 2]));
	}

	std::cout << v.back() << std::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++: #include <iostream>

using namespace std;

int fib(int);

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

    return 0;
}

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

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

int main(void){

    int  n;
    cin >>n;
    int dp[n];
    dp[0] = 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;

using ll = long long;

template<typename T> using V = std::vector<T>;
using Vi = V<int>;
using VVi = V<V<int>>;
using Vl = V<ll>;
using VVl = V<V<ll>>;
using Vs = V<string>;

template<typename T1, typename T2> using P = std::pair<T1, T2>;
using Pii = P<int, int>;
using Pll = P<ll, ll>;
using Pdd = P<double, double>;

template<typename T1, typename T2> using M = std::map<T1, T2>;
using Mii = M<int, int>;
using Msi = M<string, int>;

#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define REP2(i,s,e) for(int i=(int)(s);i<(int)(e);++i)
#define RREP(i,s,e) for(int i=(int)(s);i>=(int)(e);--i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin(),ie=(c).end();i!=ie;++i)
#define ALL(c) (c).begin(), (c).end()

const double PI = acos(-1);
const ll MOD = 1e9+7;

int n;
string s;

int main() {
    cin >> n;

    Vi dp(n+1);
    dp[0] = 1;
    dp[1] = 1;
    REP2(i, 2, n+1) {
        dp[i] = dp[i-1] + dp[i-2];
    }
    std::cout << dp[n] << '\n';

    return 0;
}