Go: package main

import (
        "fmt"
)

func main() {
        var n int
        fmt.Scanf("%d", &n)
        fmt.Println(fact(n))
}

func fact(n int) (f uint64) {
        if n < 2 {
                return uint64(1)
        } else {
                return fact(n-1) * uint64(n)
        }
}

C++: 
#include <iostream>
using namespace std;
int main(){
    double ans[20];
    int i,n;
    cin>>n;
    for(i=0;i<=n;i++){
        if(i==0){
            ans[0]=1;
        }else{
            ans[i]=ans[i-1]*i;
        }
    }
    cout<<ans[n]<<endl;
    return 0;
}

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

//const static double	de_PI	= 3.14159265358979323846;
//const static int	de_MOD	= 1000000007;
//const static int	de_MAX	= 999999999;
//const static int	de_MIN = -999999999;

int main(void) {

	//std::ifstream in("123.txt");	std::cin.rdbuf(in.rdbuf());

	int n = 0;
	std::cin >> n;

	unsigned long long pro = 1;
	for (int i = n; i >= 1; i--) {
		pro *= i;
	}

	std::cout << pro << std::endl;

}

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

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

C++: #include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;
#define INF 1000000000
typedef long long ll;
ll memo[25];

ll dfs(int n) {
    if (memo[n] > 0) return memo[n];
    if (n == 0 || n == 1) return 1;
    else return memo[n] = n * dfs(n-1);
}

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

C++: #include<cstdio>
#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
#include<string>
#include<functional>
#include<queue>
#include<stack>
#include<math.h>
#define INF 999999

using namespace std;

typedef long long ll;

ll d[22];

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

	d[1] = 1;
	for (int i = 2; i <= n; i++) {
		d[i] = d[i - 1] * i;
	}
	cout << d[n] << endl;
	
	return 0;
}

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

int main(){
  int n,i;
long long ans;

  while(cin >> n){

  ans=1;
  for(i=0;i<n;i++){
    ans=ans*(n-i);

  }
 
    cout << ans << endl;
  }

}

C++: #include <iostream>
using namespace std;
factorial(int n){
  return (--n) ? factorial(n):1;
}

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

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

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

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


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

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

int factorial(int n) {
	if(n == 1) return 1;
	else {
		return 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 n;
	unsigned long ans = 1;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		ans *= i;
	}
	cout << ans << endl;
	return 0;
}

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

C++: #include <iostream>
#include <cmath>
using namespace std;
int main() {
  int a;
  cin >> a;
  cout << tgamma(a+1) << endl;
  return 0;
}

C++: #include<stdio.h>
int main()
{
    int i,n;
    int fact = 1;
    scanf("%d",&n);
    for(i = 1;i <= n;i++)
    {
        fact = fact*i;
    }
    printf("%d",fact);


    return 0;
}

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

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


int main()
{
    long long num;

    cin >> num;

    cout << factorial(num);

    return 0;
}

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

C++: #include <iostream>
#include <sstream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <cstdio>
#include <cmath>
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
#define ALL(a)  (a).begin(),(a).end()
#define REP(i,n) for(int i=0;i<(n);++i)
const double EPS = 1e-10;
const double PI  = acos(-1.0);
#define dump(x) cerr << "  (L" << __LINE__ << ") " << #x << " = " << (x) << endl;
#define dumpv(x) cerr << "  (L" << __LINE__ << ") " << #x << " = "; REP(q,(x).size()) cerr << (x)[q] << " "; cerr << endl;
template<typename T1, typename T2>
ostream& operator<<(ostream& s, const pair<T1, T2>& d) {return s << "(" << d.first << "," << d.second << ")";}

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

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

C++: #include<iostream>

using namespace std;

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

C++: #include<stdio.h>
int main(void){
long long int a,ans,i;
ans=1;
scanf("%lld",&a);
for(i=1;i<=a;i++){
    ans=ans*i;
}
printf("%lld\n",ans);
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>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <cstring>
#include <climits>
#include <cmath>
#include <cfloat>

using namespace std;

int num;
long 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;

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

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

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

  cout<<ans;
}

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

C++: #include <stdio.h>

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

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

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

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

C++: #include <iostream>

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

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

C++: #include <stdio.h>
typedef long long LL;

int main() {
	LL F[21]; 
	F[0] = 1;
	for(int i = 1; i <= 20; ++i) F[i] = F[i - 1] * i;
	int n;
	while(~scanf("%d", &n)) {
		printf("%lld\n", F[n]);
	}
	return 0;
}

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

int main(void) {
  long long int n; cin >> n;
  cout << (int)tgamma(n+1) << endl;
  return 0;
}

C++: #include <cmath>
#include <iostream>
using namespace std;
int n;
int main() {
	cin >> n;
	cout << (long long)tgamma((long double)(n)) << endl;
}

C++: #include <iostream>
using namespace std;
long long fact(long long n){
  return n<=1?1:n*fact(n-1);
}
int main(){
  long long n;

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

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

int fact(int number) {
    long r=0;
    for(int i=number; i>=1; i--)
{
r = r*i;
}
return r;
}
 
int main() {

int num;
long result =0;

cin >> num;

result = fact(num);

cout<<result;

    
}