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
import sys, os, io
input = io.BytesIO(os.read(0, os.fstat(0).st_size)).readline

def f(u, v):
    return u * m + v

def bfs(x1, y1, x2, y2):
    q1, q2 = [], []
    q1.append((x1, y1, 1))
    q1.append((x1, y1, 2))
    dist1, dist2 = [inf] * l, [inf] * l
    dist1[f(x1, y1)], dist2[f(x1, y1)] = 0, 0
    d = 0
    while q1:
        for i, j, z in q1:
            if z == 1:
                for di, dj in v:
                    ni, nj = i, j
                    for _ in range(k):
                        ni += di
                        nj += dj
                        u = f(ni, nj)
                        if not 0 <= ni < n or not 0 <= nj < m or s[u] & 1:
                            break
                        if dist2[u] ^ inf:
                            break
                        dist2[u] = d + 1
                        q2.append((ni, nj, 2))
            else:
                for di, dj in v:
                    ni, nj = i, j
                    for _ in range(k):
                        ni += di
                        nj += dj
                        u = f(ni, nj)
                        if not 0 <= ni < n or not 0 <= nj < m or s[u] & 1:
                            break
                        if dist1[u] ^ inf:
                            break
                        dist1[u] = d + 1
                        q2.append((ni, nj, 1))
        q1, q2 = q2, []
        d += 1
    return min(dist1[f(x2, y2)], dist2[f(x2, y2)])

n, m, k = map(int, input().split())
s = []
for _ in range(n):
    s0 = list(input().rstrip())
    for i in s0:
        s.append(i)
x1, y1, x2, y2 = map(int, input().split())
v = [(1, 0), (-1, 0), (0, 1), (0, -1)]
l = n * m
inf = pow(10, 9) + 1
ans = bfs(x1 - 1, y1 - 1, x2 - 1, y2 - 1)
ans = (ans + 1) % (inf + 1) - 1
print(ans)