Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
func readInt() int64 {
    sc.Scan()
    n, _ := strconv.Atoi(sc.Text())
    return int64(n)
}


func main() {
    var ans int64 = 1
    var n int64 = readInt()
    var i int64
    for i = 1; i <= n; i++ {
        ans *= i
    }
    fmt.Println(ans)
}

C++: #include <iostream>

unsigned long long Factorial(int n)
{
	unsigned long long ans=n;
	while(--n>0)
	{
		ans *= n;
	}
	return ans;
}

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

	std::cout << Factorial(n) << '\n';
}

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

int ans = {1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600, 6227020800. 87178291200, 1307674368000, 20922789888000, 355687428096000, 6402373705728000, 121645100408832000, 2432902008176640000};

int main(){
  int a;
  scanf("%d", &a);
  printf("%d\n", ans[a - 1]);
  return 0;
}

C++: #include<iostream>

using namespace std;

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

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

using namespace std;

main(){
	int a;
	cin >> a;
	int b=0;
	long long c=a;
	int d=a;
	long long s=1;
	while(a > b+1){
		b=b+1;
		s=c*s;
		c=c-1;
	}
	printf("%lld\n",s);
}

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

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

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

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
#include <functional>

#define REP(i,n) for(int i = 0; i < (n); ++i)
using namespace std;

long factorial(int n){
	return n == 0 ? 1 : n * factorial(n-1);
}

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

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

int main()

{

    int num;
	unsigned long long int total=1;

    cout << "Please enter a number : ";
    cin >> num;

    for(int i=1; i<=num; i++)
    {
        total*=i;
    }

	printf("%llu", total);
	
    return 0;
}

C++: #include<stdio.h>

int main(void){

    int n,i;
    long long ans = 1;
    scanf("%d", &n);

    for(i = 1; i <= n; i++){
        ans *= i;
    }
    printf("%lld\n", ans);
    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) << endl;
  return 0;
}

C++: //Circumscribed Circle of a Triangle

#include<iostream>
#include<cstdio>
using namespace std;

int fac(int n){
    if(n == 0 || n == 1) return 1;
    
    return (n * fac(n -1));
}

int main(void){
    int n, res;
    
    cin >> n;
    
    res = fac(n);
    
    cout << res << endl;
    
    return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
    int n,i=2,t;cin>>t;n=t;
    for(;i<t;i++)n*=i;
    cout<<n<<endl;
}

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

int main()
{
 int x;
 long long int sum=1;
 while(cin>>x)
 {
 for(int i=1; i<=x; i++)
 {
 sum*=i;
 }
 cout<<sum<<endl;
}
return 0;
}

C++: #include <iostream>
int factorial(int n)
{
    if (n == 0) {
        return 1;
    } 
    else {
        return n * factorial(n-1);
    }
}
int main()
{
    int n;
    std::cin  >> n;
    std::cout << factorial(n) << std::endl;
}

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

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

	return 0;}

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

int kaijou(int);
int n;

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

	return 0;
}

int kaijou(int i){
	if(i == 0){
		return 1;
	} else {
		return i * kaijou(i-1);
	}
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <cstring>
#include <climits>
#include <cmath>
#include <cfloat>

using namespace std;

int num;
unsigned long int fac=1;

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

C++: #include <iostream>

using namespace std;

void Solution()
{
    int n;
    
    cin>>n;
    
    long sum = n;
    
    for(int i = 0; i < n; i++)
    {
        sum = sum * (n - 1);
        n--;
    }
    
    cout << sum << endl;
    
    return;
}

int main()
{
    Solution();
    return 0;
}

C++: #include <iostream>
using namespace std;
int main() {
	int n; cin >> n;
	long long fac = 1;
	while (--n) {
		fac *= (n+1);
	}
	cout << fac << endl;
}

C++: //
//  main.cpp
//  kyougi
//
//  Created by 寺林 一旭 on 2018/08/27.
//  Copyright © 2018年 寺林 一旭. All rights reserved.
//

#include <iostream>
#include <vector>
#include <algorithm>
#include <stdio.h>
#include <map>
using namespace std;
int main() {
    
    int num;
    int inputValue;
    vector<int> list;
  
    while(cin >> num) //getline(cin, num))
    {
        int ans=1;
        for( int i = 1; i <= num ; i++)
        {
            ans = ans * i;
        }
        cout << ans << endl;
      //  cout << digit << endl;
   //     cout << a-b <<endl;
    }
  
    
    return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <cmath>
#include <stack>
#include <vector>


using namespace std;

int main()
{
	int n;
	scanf("%d", &n);
	long long res = 1;
	for (int i = 2; i <= n; ++i)
		res *= i;
	printf("%lld\n", res);

	return 0;
}

C++: #include <iostream>

using namespace std;

int main(void) {
	int i;
	unsigned long long in;

	cin >> in;
	for(i=in;i>1;i--) {
		in*=i-1;
	}
	cout << in << endl;

	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<math.h>
#include<algorithm>
#include<string>
#define pi 3.14159
using namespace std;

long int fact(long int n) {
	long int m;
	if(n == 1) return 1;
	else {
		m =n * fact(n - 1);
		cout << m <<endl;
	}
}

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

	

	return 0;
}

C++: #include<cstdio>
typedef long long int ll;
ll f(ll n){return n==0?1:n*f(n-1);}
int main(){
  int n;scanf("%d",&n);printf("%lld\n",f(n));
}

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

int main()
{
	int n;
	
	scanf("%d", &n);
	long long total=1;
	
	for(int i = 2; i <= n; i++){
		total *= i;
	}
	
	printf("%d\n", total);
	
	return (0);
}

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

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

C++: #include <iostream>
int factorial(int i)
{
  if (i <= 1) return 1;
  else        return i * factorial(i - 1);
}
int main()
{
  int n;
  std::cin >> n;
  std::cout << factorial(n) << std::endl;
  return 0;
}

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

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

    long long int total=1;
    for(int i=1; i<=n; i++) total*=i;

    cout << total << endl;
    return 0;
}

C++: #include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
template<class t>
using table = vector<vector<t>>;
const ld eps=1e-9;

//// < "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\a.txt" > "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\b.answer"
int main() {
	int N; cin >> N;
	long long int ans = 1;
	while (N) {
		ans *= N;
		N--;
	}
	cout << ans << endl;
	return 0;
}

C++: #include<iostream>
using namespace std;
int main(){
int n;

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

C++: #include<stdio.h>
int main()
{
   long long int n;
    while(scanf("%lld",&n)==1)
    {
       long long int sum=1;
        for(long long int i=n;i>0;i--)
            sum*=i;
        printf("%lld\n",sum);
    }
}