P3079 [USACO13MAR] Farm Painting S

After several harsh winters, Farmer John has decided it is time to re-paint his farm. The farm consists of N fenced enclosures (1

\* Line 1: The number of enclosures, N. \* Lines 2..1+N: Each line describes an enclosure by 4 space-separated integers x1, y1, x2, and y2, where (x1,y1) is the lower-left corner of the enclosure and (x2,y2) is the upper-right corner. All coordinates are in the range 0..1,000,000. 第一行 一个数，牛圈的总数$n$ 第二到$n+1$行 每行四个数，起点坐标$x1,y1$和终点坐标$x2,y2$

\* Line 1: The number of enclosures that are not contained within other enclosures. FJ总共需要刷的牛圈的个数

There are three enclosures. The first has corners (2,0) and (8,9), and so on. Enclosure 3 is contained within enclosure 1, so there are two enclosures not contained within other enclosures.