Алексей Парастюк №30

#include <iostream>
#include <cmath>

using std::cout;
using std::endl;
using std::cin;


int main()
{   
    int z;
    int a;
    int b;
    int c;
    
    cout << "z = ab + ac + bc" << endl;
    cout << "Enter a,b,c:\n " << endl;
    
    cin >> a;
    cin >> b;
    cin >> c;
    
    z = a*b + a*c + b*c;
    cout << z << endl;
    
    return 0;
}