Olya loves energy drinks. She loves them so much that her room is full of empty cans from energy drinks.

Formally, her room can be represented as a field of *n* × *m* cells, each cell of which is empty or littered with cans.

Olya drank a lot of energy drink, so now she can run *k* meters per second. Each second she chooses one of the four directions (up, down, left or right) and runs from 1 to *k* meters in this direction. Of course, she can only run through empty cells.

Now Olya needs to get from cell (*x*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">1</sub>) to cell (*x*<sub class="lower-index">2</sub>, *y*<sub class="lower-index">2</sub>). How many seconds will it take her if she moves optimally?

It's guaranteed that cells (*x*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">1</sub>) and (*x*<sub class="lower-index">2</sub>, *y*<sub class="lower-index">2</sub>) are empty. These cells can coincide.
The first line contains three integers *n*, *m* and *k* (1 ≤ *n*, *m*, *k* ≤ 1000) — the sizes of the room and Olya's speed.

Then *n* lines follow containing *m* characters each, the *i*-th of them contains on *j*-th position "#", if the cell (*i*, *j*) is littered with cans, and "." otherwise.

The last line contains four integers *x*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">1</sub>, *x*<sub class="lower-index">2</sub>, *y*<sub class="lower-index">2</sub> (1 ≤ *x*<sub class="lower-index">1</sub>, *x*<sub class="lower-index">2</sub> ≤ *n*, 1 ≤ *y*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">2</sub> ≤ *m*) — the coordinates of the first and the last cells.
In the first sample Olya should run 3 meters to the right in the first second, 2 meters down in the second second and 3 meters to the left in the third second.

In second sample Olya should run to the right for 3 seconds, then down for 2 seconds and then to the left for 3 seconds.

Olya does not recommend drinking energy drinks and generally believes that this is bad.
3 4 4
....
###.
....
1 1 3 1
3
3 4 1
....
###.
....
1 1 3 1
8
2 2 1
.#
#.
1 1 2 2
-1
10 10 1
##########
#.........
#.#######.
#.#.....#.
#.#.###.#.
#.#.#.#.#.
#.#.#.#.#.
#.#.#...#.
#.#.#####.
#.#.......
6 6 10 2
48
10 10 3
##########
##########
##########
##########
##########
##########
##########
#########.
#########.
####..###.
10 6 10 5
1
10 10 3
...##..#..
#.#..#...#
..#.##.#..
##..#..#.#
..#...##..
.#.#.#....
#......#..
.#.####.##
......#...
.#.##...##
4 6 8 1
7
10 10 1000
..........
..........
..........
..........
..........
..........
..........
..........
..........
..........
7 6 1 3
2
10 10 1000
..........
..........
..........
..........
..........
..........
..........
..........
..........
.....#....
3 9 5 1
2
10 10 10
...#......
##.#.#####
...#...###
.#####.###
...#...###
##.#.#####
...#...###
.#####.###
.......###
##########
1 1 1 10
17
2 5 5
#####
##.##
2 3 2 3
0
4 4 4
...#
.#.#
....
##..
1 1 3 4
2
6 6 100
....##
.##.##
.##.##
......
###.##
###.##
1 1 4 6
2
def fuuu(x,y,ii,jj,n,m,k,sh):
  f = True
  i = 1
  global fl
  while (fl and f and i <= k
         and 0<=x+i*ii < n
         and 0<=y+i*jj < m
         ):
    if a[x+i*ii][y+i*jj]:
      f = False
      if a[x+i*ii][y+i*jj] == -2:
        fl = False
    else:
      a[x+i*ii][y+i*jj] = sh
      proo.add((x+i*ii,y+i*jj))
    i += 1

n,m,k = map(int,input().split(' '))
a = [[0]*m for i in range(n)]
for i in range(n):
  s = input()
  for j in range(len(s)):
    if s[j] == '#':
      a[i][j] = -1
x1,y1,x2,y2 = map(int,input().split(' '))
a[x2-1][y2-1] = -2
global fl
fl = True
sh = 1
pro = set()
proo = set()
pro2 = set()
pro.add((x1-1,y1-1))
pro.add((x1-1,y1-1))
pro2.add((x1-1,y1-1))
while fl and sh < n*m:
  for tt in pro2:
    x,y = tt    
    fuuu(x,y,1,0,n,m,k,sh)  
    fuuu(x,y,0,1,n,m,k,sh)
    fuuu(x,y,-1,0,n,m,k,sh)  
    fuuu(x,y,0,-1,n,m,k,sh)
  sh += 1
  pro.update(pro2)
  pro2 = proo.copy()
  proo.clear()
##print(' '.join(map(str,pro)))
if fl:
  print(-1)
else:
  print(sh-1)
##for i in range(n):
##  print(' '.join(map(str,a[i])))
