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;
#define NIL -1

int F[50];

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

int main() {
  int n; cin >> n;
  for (int i = 0;  i < 50; ++i) F[i] = NIL;
  cout << fibonacci(n) << endl;
}

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

long long dp[101];

long long fib(long long n){
  
  dp[0] = 0;
  dp[1] = 1;

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

  return dp[n];
}

int main(){

  long long n;

  cin>>n;

  memset(dp,0,101);

  cout<<fib(n)<<endl;

  return EXIT_SUCCESS;
}

C++: #include <iostream>

using namespace std;

int fib(int n);

int memo[45];

int main(){
  int n;

  cin >> n;
  cout << fib(n) << endl;
}

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

C++: #include <bits/stdc++.h>
using namespace std;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    vector<int> dp(45);
    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 <iostream>
using namespace std;

int F[50];

int main() {

    int n;
    cin >> n;
    F[0] = 1;
    F[1] = 1;
    for (int i = 2; i < 45; i++) {
        F[i] = F[i-1] + F[i-2];
    }
    cout << F[n] << '\n';
}

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

unordered_map<int, int> h;

int fib(int n);

int fib(int n) {
    if (h.count(n) != 0) {
        return h[n];
    }

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

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

C++: #include <iostream>

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

int main(void)
{
int n;
std::cin >> n;
std::cout << fib(n) << std::endl;
return 0;
}

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) << endl;

    return 0;
}

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

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

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

    cout << A[n] << endl;

    return 0;
}

C++: #include<stdio.h>

int dp[50];

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

int main() {
  int n, i;
  for (i = 0; i < 50; i++) dp[i] = -1;

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

  return 0;
}

C++: #include <stdio.h>

int fibonacci(int);

int fibo[44];

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

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

C++: # include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
constexpr int MOD = 1000000007;
constexpr int INF = 2000000000;
using namespace std;

int main() {
	int n;
	cin >> n;
	long long dp[100];
	dp[0] = dp[1] = 1;
	for (int i = 2; i <= n; i++) {
		dp[i] = dp[i - 1] + dp[i - 2];
	}
	cout << dp[n] << endl;
}

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

// ?????£??????????????°???????±???????
int fibonacci(int n);

int main()
{
    int num;
    cin >> num;
    int res = 0;

    res = fibonacci(num);
    cout << res << endl;

    getchar();
    getchar();

    return 0;
}

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

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

int memo[45];

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

int fib1(int n) {
	return (int)(pow((1 + sqrt(5)) / 2, n) / sqrt(5) + 0.5);
}

int main() {
	int n;
	cin >> n;
	fill_n(memo, 45, 0);
	cout << fib(n) << endl;
	return 0;
}

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

using namespace std;

#define Vi vector<int>
#define FOR(i,s,e) for (int i=s; i<e; i++)
#define ITER(v) v.begin(), v.end()

constexpr int N_MAX = 44;

int dp[N_MAX+1] = {};

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

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

    int n;
    cin >> n;
    cout << fib(n) << endl;

    return 0;
}

C++: #include<bits/stdc++.h>
#define max3(a,b,c) max(a,max(b,c))
#define min3(a,b,c) min(a,min(b,c))
#define MOD 1000000007
#define INF 2000000000
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define reprev(i,n) for(int (i)=(n-1);(i)>=0;(i)--)
#define Flag(x) (1<<(x))
#define Flagcount(x) __builtin_popcount(x)
#define pint pair<int,int>
#define pdouble pair<double,double>
typedef unsigned long long int ull;
typedef long long lint;
 
using namespace std;

int save[44]={};

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

int main(void){
  save[0]=1,save[1]=1;
  int N;
  cin >> N;
  cout << fibo(N) << endl;
}