#include <iostream>
using namespace std;
int main(){
float prodPI=1, i=1;
int n;
do{
cout << "introduzca numero terminos n>0 para aproximar PI: " << endl;
cin >> n;
}while(n<=3);
while(i<=n){
cout<<(i-2)+(i+2)<<", ";
//prodPI=prodPI*((2*i)*(2*i))/((2*i-1)*(2*i+1));
i=i+1;
}
cout <<"Valor aproximad de PI: " << 2*prodPI << endl;
return 0;
}