B"You work as a system administrator in a dormitory, which has n rooms one after another along a straight hallway. Rooms are numbered from 1 to n . You have to connect all n rooms to the Internet. You can connect each room to the Internet directly, the cost of such connection for the i -th room is i coins. Some rooms also have a spot for a router. The cost of placing a router in the i -th room is also i coins. You cannot place a router in a room which does not have a spot for it. When you place a router in the room i , you connect all rooms with the numbers from max(1,~i - k) to min(n,~i + k) inclusive to the Internet, where k is the range of router. The value of k is the same for all routers. Calculate the minimum total cost of connecting all n rooms to the Internet. You can assume that the number of rooms which have a spot for a router is not greater than the number of routers you have. The first line of the input contains two integers n and k ( 1 <= n, k <= 2 cdot 10^5 ) -- the number of rooms and the range of each router. The second line of the input contains one string s of length n , consisting only of zeros and ones. If the i -th character of the string equals to '1' then there is a spot for a router in the i -th room. If the i -th character of the string equals to '0' then you cannot place a router in the i -th room. Print one integer -- the minimum total cost of connecting all n rooms to the Internet. In the first example it is enough to place the router in the room 3 , then all rooms will be connected to the Internet. The total cost of connection is 3 . In the second example you can place routers nowhere, so you need to connect all rooms directly. Thus, the total cost of connection of all rooms is 1 + 2 + 3 + 4 + 5 + 6 = 21 . In the third example you need to connect the room 1 directly and "...