Injured Picture

Injured Picture

Time limit 1 second
Memory limit 64 MiB

Roman figure I, which stood on the floor of the room in point with coordinates X[0], Y[0], 0 and did not endure a relation to answer of problem of "Roman numerals". It flowed on the floor. Just as a bottom part of the Roman figure was fasted hinge, so it stayed at the place without change, but the top part of the Roman figure found oneself in point with coordinates X[1], Y[1], 0. In the room stood vertical paper picture. You know coordinates of bottom parts X[2], Y[2], 0 and X[3], Y[3], 0 and height of picture H.

Find the length "tear up of paper" on the picture.

Input data

For input you have 9 numbers X[0], Y[0], X[1], Y[1], X[2], Y[2], X[3], Y[3], H. All input data is integer numbers, which module not exceeds 10^9.

Output data

The program gives you one number. It is value with precision to 0.001 which you find.


Input example #4
1 1 6 1 4 0 4 5 6
Output example #4
Author Prysyashnjuk A.W.