Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

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

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	dp := make([]int, N+1)
	dp[0] = 1
	dp[1] = 1
	for i := 2; i <= N; i++ {
		dp[i] = dp[i-1] + dp[i-2]
	}

	fmt.Fprintln(wtr, dp[N])
	wtr.Flush()
}

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

static const int N=100;

int main(){
  int n,p[N+1],m[N+1][N+1];
  cin>>n;
  for(int i=1;i<=n;i++){
    cin>>p[i-1]>>p[i];
  }

  for(int i=1;i<=n;i++) m[i][i]=0;
  for(int l=2;l<=n;l++){
    for(int i=1;i<=n-l+1;i++){
      int j=i+l-1;
      m[i][j]=(1<<21);
      for(int k=i;k<=j-1;k++){
	m[i][j]=min(m[i][j],m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
      }
    }
  }

  cout<<m[1][n]<<endl;

  return 0;
}

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

vector<int> mm;
int fib(int n){
  if (n == 0)
    return 0;
  else if (n == 1)
    return 1;
  else if (mm[n])
    return mm[n];
  else  {
    mm[n] = fib(n-1)+fib(n-2);
    return mm[n];
    }
}

int main(){
  int n;
  cin >> n;
  mm.assign(n+2,0);

  cout << fib(n+1) << "\n";
}

C++: #include <cmath>
#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
#include<queue>
#include<set>
#include<tuple>
#include<bitset>
#include<iomanip>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
ll inf = 1000000007;
ll dp[10000005];
int main() {
	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 main()
{
    int input;
    cin >> input;

    int first = 1;
    int second = 1;
    
    for (int i = 2; i < input; ++i) {
        int third = first + second;
        first = second;
        second = thid;
    }
    cout << second;
    
    return 0;
}

C++: #define _USE_MATH_DEFINES
#include <iomanip>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <algorithm>
#include <numeric>
#include <utility>
#include <complex>
#include <functional>
#include <typeinfo>

#define REP(i, x) for (int i = 0; i < (int)(x); i++)
#define REP1(i, x) for (int i = 1; i <= (int)(x); i++)
#define RREP(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define RREP1(i, x) for (int i = ((int)(x)); i > 0; i--)
/*
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

#define all(x) (x).begin(),(x).end()
*/

using namespace std;

int x[100];

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

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

C++: #include <iostream>
using namespace std;
typedef long long ll;
#define MAX 50
ll num[MAX];
int main() {
  int n;
  cin >> n;
  num[0] = num[1] = 1;
  for (int i = 2; i <= n; i++) {
    num[i] = num[i-1] + num[i-2];
  }
  cout << num[n] << endl;
  return 0;
}

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

using namespace std;

int n;
int d[50];
int fib(int i) {
	if (d[i] > 0) return d[i];

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

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

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int calc[45];

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


int main() {
    int n;
    cin >> n;
    REP(i, 45) calc[i] = 0;
    calc[0] = 1;
    calc[1] = 1;
    cout << fib(n) << endl;
    return 0;
}

C++: #include<bits/stdc++.h>
const long long INF = INT_MAX / 2;
const long long MOD = 1000000007;
const long double PI = 3.1415926;
#define FOR(i,r,n) for(ll i = (ll)(r); i < (ll)(n); i++)
#define RFOR(i,r,n) for(ll i=(ll)(n-1);i>=r;i--)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n+1)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(x) x.begin(),x.end()
#define RALL(x) x.rbegin(),x.rend()
#define ll long long int
using namespace std;
ll ans = 0, sum = 0, n, k, cnt = 0, w, h;
string s;
vector<ll> v;
vector < pair<ll, ll > > vp;
vector<vector<ll> > vv(50, vector<ll>(50, INF));
vector<string> vs;
vector<char> vc;
set<ll> st;
map<char, ll> mp;

/*--------------------template--------------------*/

int main()
{
	cin >> n;
	ll a[100];
	fill(a,a+2, 1);
	FOR(i,2,n+1)
	{
		a[i] = a[i - 1] + a[i - 2];
	}
	cout << a[n] << endl;
}

C++: #include <iostream>

using namespace std;

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

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

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define INF 114514810
#define MOD 1000000007
#define ALL(a) begin(a),end(a)
#define MS(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(10)
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;
struct edge
{
	int from, to, cost;
	bool operator < (const edge& e) const { return cost < e.cost; }
	bool operator >(const edge& e) const { return cost > e.cost; }
};
///*************************************************************************************///
///*************************************************************************************///
///*************************************************************************************///

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