ex8

#include <iostream>
using namespace std;

int main()
{ // problema 8
 long S,p,c;
 unsigned n,i;
 S=0;p=1;c=1;
 cout<<"n=";cin>>n;
 for (i=1;i<=n;i++)
 {
    p*=i;
    S+=c*p*p;
    c*=-1;
 }
  cout<<"S="<<S;
    return 0;
}