#include <cmath>
#include <iostream>
using namespace std;

int main() {
    // Do NOT change the next few lines
    double a, b, c, d;
    cout << "Enter four values: ";
    cin >> a >> b >> c >> d;
    cout << "\na = " << a << ", b = " << b << ", c = " << c
         << ", d = " << d << "\n\n";

    // Make changes after this line
    double expr1 = 0; // change this line for expression 1
    cout << "Expression 1: " << expr1 << endl; // do not change this line

    double expr2 = 0; // change this line for expression 2
    cout << "Expression 2: " << expr2 << endl; // do not change this line

    double expr3 = 0; // change this line for expression 3
    cout << "Expression 3: " << expr3 << endl; // do not change this line

    double expr4 = 0; // change this line for expression 4
    cout << "Expression 4: " << expr4 << endl; // do not change this line

    double expr5 = 0; // change this line for expression 5
    cout << "Expression 5: " << expr5 << endl; // do not change this line

    // Add extra credit after this line
}