Long factorial

#include <stdio.h>
#include <vector>

using namespace std;

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

int main() {
	freopen("fact.in", "r", stdin);
	freopen("fact.out", "w", stdout);
	int n, carry=0, tmp=0, F[10000], last=0;
	for(int i=0; i<10000; i++) F[i]=0;
	scanf("%d", &n);
	if(n<13) {printf("%d", fact(n)); return 0;}
	F[last++]=n;
	for(int i=1; i<n; i++) {
		carry=0;
		for(int j=0; j<=last; j++) {
			tmp=F[j]*i;
			F[j]=tmp%10000 + carry;
			if(F[j]>=10000) {
				carry=tmp/10000 + F[j]/10000;
				F[j]%=10000;
			}else {
				carry=tmp/10000;
			}
		}
		if(carry>0) {
			F[++last]=carry;
			carry=0;
		}
	}
	printf("%d", F[last]);
	for(int i=last-1; i>=0; i--) {
		if(F[i]==0) {
			printf("0000");
		}
		else {
			if(F[i]<10) {
				printf("000%d", F[i]);
			}
			else {
				if(F[i]<100) {
					printf("00%d", F[i]);
				}
				else {
					if(F[i]<1000) {
						printf("0%d", F[i]);
					}
					else {
						printf("%d", F[i]);
					}
				}
			}
		}
	}
	return 0;
}