Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	fmt.Fprintln(writer, fib(n))
	writer.Flush()

}

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

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

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


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

int main (){

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

}

C++: #include <iostream>

using namespace std;

int main()
{
	int a=1,b=1,n;
	cin>>n;
	for (int i=0; i<n-1; i++) {
		swap(a,b);
		a+=b;
	}
	cout<<a<<endl;
}

C++: #include <iostream>

const int MAX_SIZE = 44 + 1;

int main() {
  int f[MAX_SIZE] = {0};
  
  int n = 0;

  std::cin >> n;

  f[0] = 1;
  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;

int N;
unsigned long memo[50] = {};

unsigned long fibo(unsigned n)
{
	if (n <= 1) return 1;
	if (memo[n] == 0) {
		memo[n] = fibo(n - 1) + fibo(n - 2);
	}
	return memo[n];
}

int main()
{
	cin >> N;

	cout << fibo(N) << endl;

	return 0;
}

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

int f[50];

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

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

	fill(f, f + 50, 0);

	int N; cin >> N;
	cout << fib(N) << endl;
}

C++: #include <iostream>
using namespace std;
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <functional> //sort(A,A.end(),greater<int>());???????????????
#include <queue>
#include <stack>
#include <vector>

#define INF 10 << 10

int main() {
	int n;
	int dp[64];
	dp[0] = 1; dp[1] = 1;

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

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define INT_MAX 2147483647
#define INT_MIN -2147483646
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;

vector<ll> A(100);

int main() {
	int n;
	cin >> n;
	if (n == 0) cout << 1 << endl;
	else if (n == 1) cout << 1 << endl;
	else {
		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<iostream>
using namespace std;

int A[51];

void func(int n){
  if(n==50) return;
  A[n]=A[n-1]+A[n-2];
  func(n+1);
}

int main(){
  int n;
  cin >> n;
  A[0]=1; A[1]=1;
  func(2);

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

C++: #include <cstdio>

using namespace std;

int sum = 0;

int fib( int n ){

    if( n >= 0) {

        if( n == 0 || n == 1 ){

            return 1;

        } else {

            sum = fib( n - 1 ) + fib( n - 2 );        

        }

    } else return 0;

    return sum;

}

int main(){

    int n;

    scanf("%d", &n);

    int ans = fib(n);

    printf("%d\n", ans);

}

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

int fib[46]={};
int n = 0 ;

int main(){
    
	cin >> n ;

	fib[0]=1;
	fib[1]=1;

	for(int i=2; i<46; i++){
	
	fib[i]=fib[i-1]+fib[i-2];
	
	}


cout << fib[n] << endl ;

  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <string>
#include <queue>
#include <stack>
#include <functional>
#include <complex>
#include <cmath>
#include <ccomplex>
using namespace std;

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

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

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

C++: #include<cstdio>

int f(int n)
{
    if(n==1||n==0) return 1;
    else return f(n-1)+f(n-2);
}
int main()
{
    int n;
    while(~scanf("%d",&n)) printf("%d\n",f(n));
    return 0;
}

C++: #include<iostream>
#include<string>
#include<stdlib.h>
#include<stdio.h>
#include<vector>
#include<algorithm>
#include<deque>
using namespace std;
long long int memo[45];
long long int fib(int n)
{
	if (n < 0)return 0;
	if (memo[n] != -1500)return memo[n];
	if (n == 0 || n == 1)return 1;
	long long int ans = 0;
	ans += fib(n - 1) + fib(n - 2);

	return memo[n]=ans;
	
}

int main()
{
	int n; cin >> n; for (int i = 0; i < 45; i++)memo[i] = -1500;
	cout << fib(n) << endl;
}

C++: #include<cstdio>
#include<iostream>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<list>
#include<map>
#include<algorithm>

using namespace std;

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

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

    cout << dp[n] << endl;

    return 0;
}

C++: #include <bits/stdc++.h>
#include<algorithm>
#define int long long
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
static const double pi = 3.141592653589793;
#define MOD 1000000007
#define INF 10000000000000

int calc(int m, int n){
int ans=1;
while(n>0){
  if(n&1) ans=m*ans%MOD;
  m=m*m%MOD;
  n>>=1;
}
return ans;
}

int kinv(int k){
  return calc(k,MOD-2);
}

int fib[46];
signed main(){
  rep(i,46){fib[i]=0;}
  fib[0]=1;
  fib[1]=1;
  rep(i,44){
    fib[i+2]=fib[i]+fib[i+1];
  }
  int n;
  cin>>n;
  cout<<fib[n]<<endl;
}

C++: //INCLUDE
//------------------------------------------
#include <bits/stdc++.h>
//DEFINE
//------------------------------------------
#define ll long long
#define ld long double
#define ALLv(a)  (a).begin(),(a).end()
#define ALL(a,n)  (a),(a)+n
#define vi vector<long long>
#define vd vector<long double>
#define vs vector<string>
#define dcml(n) fixed<<setprecision(n)
//CONST
//------------------------------------------
const ll INF=1010000000000000017LL;
const ll MOD=1000000007LL;
const ld EPS=1e-12;
const ld PI=3.14159265358979323846;
//REPEAT
//------------------------------------------
#define   FOR(i,m,n) for(ll (i)=(m);   (i)<(n);  (i)++)
#define  FORS(i,m,n) for(ll (i)=(m);   (i)<=(n); (i)++)
#define  RFOR(i,m,n) for(ll (i)=(n)-1; (i)>=(n); (i)--)
#define RFORS(i,m,n) for(ll (i)=(n);   (i)>(n);  (i)--)
#define   REP(i,n)   for(ll (i)=0;     (i)<(n);  (i)++)
#define  REPS(i,x)   for(ll (i)=1;     (i)<=(x); (i)++)
#define  RREP(i,x)   for(ll (i)=(x)-1; (i)>=0;   (i)--)
#define RREPS(i,x)   for(ll (i)=(x);   (i)> 0;   (i)--)
#define  WREP(i,in,j,jn) REP(i,in)REP(j,jn)
#define WREPS(i,in,j,jn) REPS(i,in)REPS(j,jn)
//-----------------------------------------
//namespace
using namespace std;
//ライブラリはここに
//↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

//-----------------------------------------
int main(void){
    ll N;cin>>N;
    ll dp[N+1];dp[0]=dp[1]=1;
    FORS(i,2,N){
        dp[i]=dp[i-1]+dp[i-2];
    }
    cout<<dp[N]<<"\n";
}