using System;

namespace SquareFinder
{
    /// <summary>
    /// Summary description for IGrid.
    /// </summary>
    /// 

    interface IGrid 
    {
        int CountBlocksSet(int x1, int x2, int y1, int y2);
    }

    enum Shape 
    {
        Square,
        Rectangle,
        Unknown
    }

    class Grid : IGrid 
    {
        int left;
        int right;
        int bottom;
        int top;

        public int TotalCalls = 0;

        public Grid(int left, int right, int bottom, int top) 
        {
            this.left = left;
            this.right = right;
            this.bottom = bottom;
            this.top = top;
        }

        public int CountBlocksSet(int x1, int x2, int y1, int y2) 
        {
            ++TotalCalls;
            int intersectRight = Math.Min(x2, this.right);
            int intersectLeft = Math.Max(x1, this.left);
            int intersectTop = Math.Min(y2, this.top);
            int intersectBottom = Math.Max(y1, this.bottom);
        
            if (intersectRight <= intersectLeft)
                return 0;
            if (intersectTop <= intersectBottom)
                return 0;

            return (intersectRight - intersectLeft) * (intersectTop - intersectBottom);
        }
    }
}