Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func main() {
	scanner.Split(bufio.ScanWords)

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

C++: #include<bits/stdc++.h>
using namespace std;
 
#define REP(i,s,n) for(int i=s;i<n;++i)
#define rep(i,n) REP(i,0,n)
#define SORT(c) sort((c).begin(),(c).end())
#define IINF INT_MAX
#define LLINF LLONG_MAX
 
typedef long long ll;
typedef pair<int, int> ii;
 
int main(){

	int n;
	cin >> n;
	ll ans = 1;
	REP(i, 2, n+1){
		ans *= (ll)i;
	}
	
	cout << ans << endl;
	
	return 0;
}

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

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

	int f = 1;
	for ( int i = 2; i <= n; i++ )
	{
		f *= i;
	}

	cout << f << endl;

}

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

int factorial(int n){
	int 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<iostream>
#include<string>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<cmath>

using namespace std;

#define N 10005   
int main(){
	int i,j,len;
	int n;
	while(scanf("%d",&n) != EOF) {  
		if(n == 0 || n == 1) {
			printf("1\n");
			continue;
		}
		long s[N]={1, 1};
		len = 1;
		for(i = 2;i <= n; i ++){
			for(j = 0; j < len; j ++)
				s[j] = s[j] * i;
			for(j = 0;j < len - 1; j ++) {
				s[j + 1] += s[j] / 10000;
				s[j] = s[j] % 10000;
			}
			if(s[j] > 10000 ) {
				s[j + 1] = s[j] / 10000;
				s[j] = s[j] % 10000;
				len ++;       
			}
		}
		printf("%d",s[len - 1]);
		for(j = len - 2; j >= 0; j --)
			printf("%04d", s[j]);
		printf("\n");
	}   
	return 0;
}

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

long kaijou(long);
long n;

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

	return 0;
}

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

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

using namespace std;
using ll = long long;
using pii = pair<int, int>;

int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  
  ll n, ans = 1;
  cin >> n;
  while (n > 1) ans *= n--;
  cout << ans << 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 << i << endl;
    return 0;
}

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

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

C++: #include <stdio.h>

int fac(int n)
{
    int i,f=1;
    for(i=2;i<=n;i++)
    {
        f*=i;
    }
    
    return f;
}

int main(void)
{
    int n;
    
    scanf("%d",&n);
    printf("%d\n",fac(n));
    
    return 0;
}

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

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

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef pair<ll, int> li;
typedef pair<int, ll> il;
typedef vector<ii> vii;
typedef vector<il> vil;
typedef vector<li> vli;

#define F first
#define S second
#define pb(x) push_back(x)
#define mp(a,b) make_pair(a,b)
#define sz size()
#define all(A)    A.begin(), A.end()
#define mem(a, b) memset(a, b, sizeof(a))
#define f0(i,b)   for(int i=0;i<(b);i++)
#define f1(i,b)   for(int i=1;i<=(b);i++)
#define f2(i,a,b) for(int i=(a);i<=(b);i++)
#define fr(i,b,a) for(int i=(b);i>=(a);i--)
#define rep(i,a,b,c) for(int i=(a);i!=(b);i+=(c))
#define mod 1000000007

#define forr(i,n)    for(i=0; i<n; i++)
#define whilee(i,t)  while(i!=t)
#define  sl(a)  scanf("%lld",&a)
#define  pl(a)  printf("%lld",a)

//for(auto it =A.begin(); it!=A.end(); it++)
//sort(A.begin(),A.end());
//binary_search(A.begin(),A.end(),x);
//reverse(A.begin(), A.end());
//cout << *max_element(A.begin(), A.end());
//cout << *min_element(A.begin(), A.end());
//count(A.begin(), A.end(), X); //counts the occurrences of X
//distance(A.begin(),A.end());  //distance between first to last element
//accumulate(A.begin(), A.end(), 0); //add
//next_permutation(A.begin(), A.end());
//prev_permutation(A.begin(), A.end());
//swap(S[0], T[0]);
//scanf("%d",&x);
//printf("%d\n",x);

//vector <int> A;
//deque <int> A;
//queue <int> A;
//stack <int> A;
//set <int> A;
//map <int,int> A;
//pair <int,int> A ;
//vector <pair <int,int>> A ;
//char ch;
//string S, T, U;
ll factorial(ll n)
{
    if(n==1)
    {
        return 1;
    }
    else
    {
        return n*factorial(n-1);
    }
}
ll i, j, k, a, b, c, d, f, g, h, l, m, n, p, q, r, s, t, w, x, y, z, maxx=INT_MIN, minn=INT_MAX, ans=0, sum=0, cnt=0;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    scanf("%lld",&n);
    printf("%lld", factorial(n));

    return 0;
}

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

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

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>
#include <sstream>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <numeric>
#include <cmath>
#include <climits>
#include <limits>
#include <cfloat>
#include <fstream>
using namespace std;

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

int main()
{
	string str = "";

	while (getline (cin, str )){
		long res;
		long n;
		stringstream ssn(str);
		ssn >> n;
		res = factorial(n);
		cout << res << endl;	
	} // end while
		
	return 0;
}

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


int main(void){


    long long int n,fact = 1;

    cin >> n;

    for(int i = n;i > 0;i--){
        fact *= i;
    }

    cout << fact << endl;
    return 0;
}

C++: #include<stdio.h>

int main(void)
{
	int n,i;
	long long int sum;

	sum=1;

	scanf("%d",&n);

	for(i=1;i<=n;i++){
		sum*=1;
	}
	
	printf("%lld\n",sum);

	return 0;
}

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

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

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

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

int main()
{
    long long n;

    cin >> n;

    cout << factorial(n) << endl;
    return 0;
}

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

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

C++: #include <stdio.h>

int main() {
    long long n = 0;
    long long result = 1;
    scanf("%d", &n);

    for (long long i = n; 1 < i; --i) {
        result *= i;
    }

    printf("%lld\n", result);

    return 0;
}

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

int main(){
  int n;
  int ans=1;
  
  for(int i=1;i<=n;i++){
    ans*=i;
  }
  
  printf(" %d",ans);
  
  return 0;
}