import Data.List
type Board = [[Int]]
a&x|(u,_:v)<-break(==x)a=u:v&x|let=[a]
printfield :: Board -> String
printfield = intercalate "\n".map printrow
printrow :: [Int] -> String
printrow = concatMap show
createField :: [Int] -> Board
createField [x,y] = 0<$[0..x]<$[0..y]
drawPixel :: (Int,Int) -> Board -> Board
drawPixel (x,y) m|(l,h:r)<-splitAt x m,(u,v:d)<-splitAt y h=l++(u++(v+1):d):r
drawLine [x,y] [a,b] m = foldr drawPixel m [(u,v)|u<-[x..a],v<-[y..b]]
minmax x=map(maximum.(x>>=))[head,last]
p::[String] -> [[Int]]
p[s,_,t]=map(map read.(&','))[s,t]
main=interact$printfield.drawLine [1,0][1,2].drawLine [0,0] [4,0].createField.minmax.map(p.words).lines