B"Iahub and his friend Floyd have started painting a wall. Iahub is painting the wall red and Floyd is painting it pink. You can consider the wall being made of a very large number of bricks, numbered 1, 2, 3 and so on. Iahub has the following scheme of painting: he skips x xe2 x80 x89- xe2 x80 x891 consecutive bricks, then he paints the x-th one. That is, he'll paint bricks x, 2 xc2 xb7x, 3 xc2 xb7x and so on red. Similarly, Floyd skips y xe2 x80 x89- xe2 x80 x891 consecutive bricks, then he paints the y-th one. Hence he'll paint bricks y, 2 xc2 xb7y, 3 xc2 xb7y and so on pink. After painting the wall all day, the boys observed that some bricks are painted both red and pink. Iahub has a lucky number a and Floyd has a lucky number b. Boys wonder how many bricks numbered no less than a and no greater than b are painted both red and pink. This is exactly your task: compute and print the answer to the question. The input will have a single line containing four integers in this order: x, y, a, b. (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89x, xe2 x80 x89y xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000, 1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89a, xe2 x80 x89b xe2 x80 x89 xe2 x89 xa4 xe2 x80 x892 xc2 xb7109, a xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89b). Output a single integer -- the number of bricks numbered no less than a and no greater than b that are painted both red and pink. Let's look at the bricks from a to b (a xe2 x80 x89= xe2 x80 x896, xe2 x80 x89b xe2 x80 x89= xe2 x80 x8918). The bricks colored in red are numbered 6, 8, 10, 12, 14, 16, 18. The bricks colored in pink are numbered 6, 9, 12, 15, 18. The bricks colored in both red and pink are numbered with 6, 12 and 18. "...