Go: package main

import "fmt"

func main() {
	var n int
	fmt.Scan(&n)

	rs := 1
	for i := 1; i <= n; i++ {
		rs *= i
	}
	fmt.Println(rs)
}

C++: #include <algorithm>
#include <vector>
#include <math.h>
#include <stdio.h>
#include <cctype>
#include <iostream>
#include <set>
#include <string>
#include <queue>
#include <map>
using namespace std;
int size(string x){
	string::size_type size=x.size();
	return size;
}
#define fu(l,k) for(int i=l;i<k;i++)
#define fd(l,k) for(int i=l;i>k;i--)
#define fi first
#define se second
typedef  vector<string> vs;
typedef  vector<int> vi;
double pi(){
	return M_PI;
}
typedef set<int> set_i;
typedef set<string> set_s;
int main(){
	int n,ans=1;
	cin>>n;
	fd(n,0){
		ans*=i;
	}
	cout<<ans<<endl;
}

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

long long factoria(long long t)
{
	if (t == 0 || t == 1) return 1;
	return t*factoria(t - 1);
}

int main()
{
	long long a,ans;
	cin >> a;
	ans = factoria(a);
	cout << ans ;
	return 0;
}

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

int main()
{
	ll n, res = 1;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		res *= i;
	}
	cout << res << endl;
	return 0;
}

C++: #include <iostream>

using namespace std;

long factorial(long n){
    if(n == 0 || n == 1)
        return 1;
    else{
        return n * factorial(n - 1);
    }
}

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

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

int main(){
	int n;
	ll fac=1;
	cin>>n;
	for(int i=1;i<=n;i++){
		fac*=i;
	}
	cout<<fac<<endl;
	return 0;
}

C++: #include <iostream>

using namespace std;

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

    long long p = 1;

    for(int i = 1; i <= N; i++) {
        p *= i;
    }
    cout << p << endl;
    return 0;
}

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

using namespace std;

int main(){
    int a,tot = 1;
    cin >> a;
    while(a >= 1){
        tot *= a;
        a -= 1;
    }
    cout << tot << endl;
    return 0;
}

C++: #include <iostream>

using namespace std;
int main(void)
{
    int n;
    cin >> n;
    long long int res = 1;
    for(int i=1;i<=n;i++)
        res *= (long long int)i;
    cout << res << endl;
    return 0;
}

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

int main(){
	long long int n, a = 1;

	cin >> n;
	for(int i=1 ; i<=n ; i++){
		a *= i;
	}
	cout << a << endl;
}

C++: #include <iostream>

using namespace std;

int fact(int n) {
    if(n == 1) {
        return 1;
    }
    
    return n * fact(n - 1);
}

int main() {
    int num;
    
    cin >> num;
    
    if(1 <= num && num <= 20)
        cout << fact(num) << endl;
    
    return 0;
}

C++: #include <iostream>
//#include <fstream.h>
//#include <cstring>
using namespace std;

long int factorial(int n) {
  int i,x=1;
  for(i=1;i<=n;i++) {
    x*=i;
  }
  return x;
}

int main() {
  
  int n;

  cin >> n;

  cout << factorial(n) << "\n";

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
long long dp[21];
int main(void){
    dp[0] = 1;
    for(int i=1; i<21; ++i) dp[i] = i*dp[i-1];
    int n;
    cin >> n;
    cout << dp[n] << endl;
}

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

int main(){
    int n;
    int k=1;
    cin>>n;
    int i;
    for(i=1;i<=n;i++){
        k*=i;
    }
    cout<<k<<endl;
    return(0);
}

C++: #include<iostream>
main(){long long n,i;for(std::cin>>n,i=n;i>1;n*=--i);std::cout<<n<<"\n";}

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

int main(){
  int n;
  cin >> n;
  long long int res=1;
  while(n!=1){
    res *= n;
    n--;
  }
  cout << res << endl;
}

C++: #include <iostream>
using namespace std;
int main(void){
    // Here your code !
    int n;
    long long int a=1;
    cin>>n;
    
    for(int i=1;i<=n;i++){
        a=a*i;
    }
    cout<<a<<endl;
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <utility>
#include <string>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <string.h>
#include <deque>
#define REP(i,j,n) for(int i=j;i<n;i++)
#define SORT(x) sort(x.begin(),x.end())

using namespace std;



int main() {
	int n;
	long long sum = 1;
	cin >> n;
	while (n > 1 ){
		sum *= n;
		n--;
	}

	cout << sum << endl;
	return 0;
}

C++: //NoorBaizura bt Mohd Zin
// 1111168

#include <iostream>

using namespace std;

int main()
{
    int x,count=1;
    
    cin >> x;
    
    for (int i=1; i<=x; i++)
    {
        count *= i;
    }
    
    cout << count;
    
//    system ("pause");
    return 0;
    
}

C++: #include<iostream>
int main(){
	int n;
	std::cin>>n;
	int a=1;
	if(n<=12){
		for(int i=1;i<=n;i++){
			a*=i;
		}
		std::cout<<a<<std::endl;
	}
	else if(n==13)std::cout<<355687428096000/16/15/14/13<<std::endl;
	else if(n==14)std::cout<<355687428096000/16/15/14<<std::endl;
	else if(n==15)std::cout<<355687428096000/16/15<<std::endl;
	else if(n==16)std::cout<<355687428096000/16<<std::endl;
	else if(n==17)std::cout<<355687428096000<<std::endl;
	else if(n==18)std::cout<<355687428096000*18<<std::endl;
	else if(n==19)std::cout<<355687428096000*18*19<<std::endl;
	else if(n==20)std::cout<<355687428096000*18*19*20<<std::endl;
	

	return 0;
}

C++: #include<iostream>

using namespace std;

int factorial(int n){
  unsigned long long int ans;
  if(n==0)
    ans=1;
  else
    ans =n*factorial(n-1);
  return ans;
}

int main(){
  int n=0;
  cin>>n;

  unsigned long long int ans=1;
  ans=factorial(n);

  cout<<ans;
}

C++: #include <stdio.h>

int main(void)
{
	int n;
	int i;
	int i2;
	
	scanf("%d", &n);
	
	i2 = n;
	
	for (i = 1; i < n; i++){
		i2 *= i;
	}
	
	printf ("%d\n", i2);
	
	return (0);
}

C++: #include<iostream>
#include<cmath>
#include<cstdio>

using namespace std;

int main(){
	int n;

	while (cin >> n){

		double ans = 1;

		while (n){
			ans *= n;
			n--;
		}

		printf("%.0f\n", ans);
	}

	return 0;
}

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

long factorial(int n){
	long ans = 1;
	for(int i = n; i > 0; --i)
		ans *= i;
	return ans;
}

int main(){
	int input;
	cin >> input;
	cout << factorial(input) << endl;
	return 0;
}

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


int main(){
int a;
long long sum=1;
	cin>>a;
	for (int i = a; i > 0; --i) {
		sum*=i;
	}
cout<<sum<<endl;
}

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

int main() {
	int n;
	cin>>n;
	long i,s=1;
	for(i=1;i<=n;i=i+1){
		s=s*i;
	}
	cout<<s<<endl;
}

C++: #include<iostream>


using namespace std;

int main(void)
{
unsigned int n;
cin>>n;
unsigned long long int ans=n;
while(n>1){
    ans*=--n;
}
cout<<ans<<endl;

return 0;
}

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

int main(){
	int N;
	cin>>N;
	ll res=1;
	for(int i=1;i<=N;i++){
		res*=(ll)i;
	}
	cout<<res<<endl;
	return 0;
}

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

int factorial(int num) {
    if(num == 1) return(1);
    return(num * factorial(num - 1));
}

int main(void) {
    int num; cin >> num;
    cout << factorial(num) << endl;
    return(0);
}

C++: #include <iostream>
#include <cstdio>
using namespace std;
int main(){
    int n;
	cin >> n;
    long long int x = 1;
    for(int i=0; i<n; ++i){
		x = x*(i+1);
    }
    cout << x;
	return 0;
}

C++: #include<iostream>

using namespace std;

int main()
{
	int n;
	__int64 ans=1;
	
	cin >> n ;
	
	for(int i=1;i<=n;i++)
	{
		ans*=i;	
	}
	
	cout << ans << endl;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
	long long n,h=1;
	cin>>n;
	for(int i=n;i>1;i--)
		h*=i;
	cout<<h<<endl;
	return 0;
}

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

int factorial(int n){
  if(n==0)return 1;
  else return n*factorial(n-1);
}

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

C++: #include <iostream>
using namespace std;
 
int main()
{
int n;
long f=1;
cin>>n;
for(int i=1;i<=n;i++)
f=f*i;
cout<<f<<"\n";
return 0;
}