#include <bits/stdc++.h>
using namespace std;
const int dx[8] = {0, 0, -1, 1, -1, -1, 1, 1};
const int dy[8] = {-1, 1, 0, 0, -1, 1, -1, 1};
int r, c, k, x, y, a, b;
vector<vector<int>> dist;
vector<string> s;
array<int, 5> nxt, cur;
deque<array<int, 5>> dq;
inline bool Valid(array<int, 5> inp)
{
return (0 <= inp[0] && inp[0] < r &&
0 <= inp[1] && inp[1] < c &&
(inp[2] < 4 || inp[3] < k) &&
inp[4] <= k &&
dist[nxt[0]][nxt[1]] == 1e9);
}
inline void Expand()
{
for (int i = 0; i < dq.size(); ++i)
{
for (int j = 0; j < 4; ++j)
{
nxt[0] = dq[i][0] + dx[j];
nxt[1] = dq[i][1] + dy[j];
nxt[2] = -1;
nxt[3] = 0;
nxt[4] = 0;
if (Valid(nxt) && s[nxt[0]][nxt[1]] == '.')
{
dist[nxt[0]][nxt[1]] = dist[dq[i][0]][dq[i][1]];
dq.push_back(nxt);
}
}
}
}
inline void Explode(int val)
{
deque<array<int, 5>> temp;
while (!dq.empty())
{
cur = dq.front();
dq.pop_front();
for (int i = 0; i < 8; ++i)
{
nxt[0] = cur[0] + dx[i];
nxt[1] = cur[1] + dy[i];
nxt[2] = i;
nxt[3] = 1 + cur[3] * (cur[2] == nxt[2]);
nxt[4] = cur[4] + 1;
if (Valid(nxt))
{
dist[nxt[0]][nxt[1]] = val;
dq.push_back(nxt);
temp.push_back({nxt[0], nxt[1], -1, 0, 0});
}
}
}
swap(dq, temp);
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> r >> c >> k >> x >> y >> a >> b;
x--;
y--;
a--;
b--;
dist.resize(r, vector<int>(c, 1e9));
s.resize(r);
for (int i = 0; i < r; ++i)
{
cin >> s[i];
}
if (s[x][y] == '#')
{
for (int i = x - k + 1; i <= x + k - 1; ++i)
{
for (int j = y - k + 1; j < y + k - 1; ++j)
{
if (0 <= i && i < r && 0 <= j && j < c)
{
dist[i][j] = 1;
dq.push_back({i, j, -1, 0, 0});
}
}
}
}
else
{
dist[x][y] = 0;
dq.push_back({x, y, -1, 0, 0});
}
for (int i = 1; !dq.empty(); ++i)
{
Expand();
Explode(i);
}
cout << dist[a][b];
return 0;
}
