
123  ZOJ Monthly, January 2013  B
There's a rope placed in twodimensional plane, Bob will paint or erase some rectangle regions in this plane(effective on the boundary). All the regions are parallel to the axis. Your task is to calculate how long the stained rope is. Input
The input will consist of multiple testcases. OutputEach testcase should output exactly 1 lines, each line a real number which is the answer, the output should rounded to two digits after the decimal point.. Sample Input2 2 1 1 1 4 4 0 2 2 3 3 0 0 5 5 Sample Output2.83 Hint
Author: CHEN, Cong 