#include <stdio.h>
#include <conio.h>

//s = a! + b! + c! voi a , b , c > 0
// ta dai dien ra bien n
//neu cho an toan khi lo minh nhap cai duoi truoc thi nen de nguyen mau ham cho an toan 

void nhap(int &);
int tinhgiaithua(int n);

void nhap(int &n)
{
	do
	{
		printf("\nhay nhap vao so nguyen duong n : ");
		scanf("%d",&n);
		if (n <= 0)
		{
			printf("\ngia tri khong hop le , xin kiem tra lai");
		}
	} while (n <= 0);
}
int tinhgiaithua(int n)
{
	int tich = 1;
	for (int i = 2; i <= n; i++)
	{
		tich *= i;
	}
	return tich;
}


int main()
{     
	int a , b , c; // khai bao 

	nhap(a);
	nhap(b);
	nhap(c);

	int s = tinhgiaithua (a) + tinhgiaithua (b) + tinhgiaithua (c);
	printf("\ns = a! + b! + c! = %d! + %d! + %d! = %d",a , b ,c, s);


	getch();
	return 0;



}