#include <iostream>
#include <vector>

using namespace std;

class Scalar_product
{
    public:
    Scalar_product(vector<double> a, vector<double> b);
};
double scalar_product(vector<double> a, vector<double> b)
{
    double product = 0;
    for (int i = 0; i <= a.size()-1; i++)
        for (int i = 0; i <= b.size()-1; i++)
            product = product + (a[i])*(b[i]);
    return product;
}