using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
    }
}
public struct Triangle
{
    public int h;
    public int b;

    public Triangle(int h, int b)
    {
        this.h = h;
        this.b = b;
    }
    public int Surface()
    {
        return h * b / 2;

    }

}

private static void Main(string[] args)
{
    Triangle[] triangles = new Triangle[3];
    for (int i = 0; i < triangles.Length; i++)
    {
        Console.Write("Triangle"+(i+1)+"b:");
        triangles[i].b = int.Parse(Console.ReadLine());
        Console.Write("Triangle" + (i + 1) + "h:");
        triangles[i].h = int.Parse(Console.ReadLine());
    }
    for (int i = 0; i < triangles.Length; i++)
    {
        Console.WriteLine("triangle " + (1 + i) + "surface area:" + triangles[i].Surface()); ;
    }
}