#include <iostream>
using namespace std;
int Giaithua(int n)
{
    if (n == 1)
        return 1;
    return n * Giaithua(n - 1);
}
int main()
{
    int n;
    cin >> n;
    cout << "Giai thua " << n << " la: " << Giaithua(n);
    return 0;
}

Segmentation fault