Instructors of Some Informatics School make students go to bed. The house contains n rooms, in each room exactly b students were supposed to sleep. However, at the time of curfew it happened that many students are not located in their assigned rooms. The rooms are arranged in a row and numbered from 1 to n . Initially, in i -th room there are a i students. All students are currently somewhere in the house, therefore a 1 + a 2 + ... + a n = nb . Also 2 instructors live in this house. The process of curfew enforcement is the following. One instructor starts near room 1 and moves toward room n , while the second instructor starts near room n and moves toward room 1 . After processing current room, each instructor moves on to the next one. Both instructors enter rooms and move simultaneously, if n is odd, then only the first instructor processes the middle room. When all rooms are processed, the process ends. When an instructor processes a room, she counts the number of students in the room, then turns off the light, and locks the room. Also, if the number of students inside the processed room is not equal to b , the instructor writes down the number of this room into her notebook (and turns off the light, and locks the room). Instructors are in a hurry (to prepare the study plan for the next day), so they don't care about who is in the room, but only about the number of students. While instructors are inside the rooms, students can run between rooms that are not locked and not being processed. A student can run by at most d rooms, that is she can move to a room with number that differs my at most d . Also, after (or instead of) running each student can hide under a bed in a room she is in. In this case the instructor will not count her during the processing. In each room any number of students can hide simultaneously. Formally, here is what's happening: A curfew is announced, at this point in room i there are a i students. Each student can run to another room