Cautious judge
Tomorrow, the football match between two famous teams: Gazmyasom and Neftrybom. The match will take place on the field of length L and width W. The match will be judged a professional football referee in the fourth generation Benjamin Khlebnikov. To be a judge - the responsible and do not always safe to do. Therefore, Benjamin decided to work out some game episodes that occur in tomorrow's game. Consider the situation where player A makes a pass to the player B - that is, passes the ball along the line segment connecting the points in which there are gamblers. On the one hand, the judge should well see what happens during a pass, on the other hand, according to security requirements, the judge can not be too close to the ball. Therefore, during the pass the judge should be located not less than r, and no more than R, from the possible position of the ball. It is assumed that all the time during which the ball moves, the judge standing in one place. Of course, the judge must always be on the game field.
Since these conditions are quite complex, even an experienced judge is sometimes difficult to determine where it should be in the moment pass. For this reason, Benjamin wants to practice before the game and find those areas where it can be, for different initial conditions. In order to compare your answer with the correct, he needs a program which, given the dimensions of the field, the coordinates of the players and the numbers r and R is the area of those areas of the field, which can be the judge. Help him!
Input
The first line of the input file are given two positive integers L and W (1 ≤ L, W ≤ 100) - the length and width of the field.
In the second row are integers X_A, Y_A, X_B, Y_B — the coordinates of the players A and B, respectively. Since the players are on the field, then 0 ≤ X_A, X_B ≤ L, 0 ≤ Y_A, Y_B ≤ W.
In the third row are integers r and R (0 < r < R < 100). It is known that R ≤ D, where D - distance between players A and B.
Output
The output file output response to a problem with an accuracy of 10^{−6}.