Rectangular division

Given N rectangles with sides, parallel to the coordinate axes. Required to determine how many parts of these rectangles divide the plane (inside the parts should not be a boundary of the rectangle).

Input

The first line contains the number of rectangles N (1 ≤ N ≤ 100). Next N lines, each containing four numbers: x_1, y_1, x_2, y_2 - coordinates of two opposite corners of the rectangle. All coordinates are integers and absolute value does not exceed 10000.

Output

Derive a single number - the number of parts into which the plane.

Examples