Write a recursive function to find the factorial of n

Write recursive function int Fac (int n) to find the factorial of n, then the main function calls the recursive function to calculate S = M! + N! ( M <= 10, N <= 10) values.
The so-called factorial means 2 multiplied by 3 1 from 4 multiplied by up to a desired number. Factorial symbol "!" To indicate, for example, 5 factorial is 5! = 1 * 2 * 3 * 4 * 5.

#include <iostream>
#include "SumOfFactorial.h"
using namespace std;
int Fac(int n)
{
    if(n==0||n==1)
 {
  return 1;
 }
 else
 {
  return n*Fac(n-1);
 }
}
int main()
{
    int M, N, sum = 0;
    cin >> M >> N;
    sum = Fac(M) + Fac(N);
    cout << M << "!+" << N << "!=" << sum << endl;
}