#include <iostream>
#include <deque>
#include <vector>
using namespace std;
const int INF = 1e9;
const int MAX = 2005;
int R, C, N;
int Sr, Sc, Gr, Gc;
char grid[MAX][MAX];
int dist[MAX][MAX];
bool visited[MAX][MAX];
int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, -1, 1};
bool in_bounds(int x, int y) {
return x >= 0 && x < R && y >= 0 && y < C;
}
int main() {
cin >> R >> C >> N;
cin >> Sr >> Sc;
cin >> Gr >> Gc;
Sr--; Sc--; Gr--; Gc--;
for (int i = 0; i < R; ++i)
cin >> grid[i];
for (int i = 0; i < R; ++i)
for (int j = 0; j < C; ++j)
dist[i][j] = INF;
deque<pair<int, int>> dq;
dq.push_front({Sr, Sc});
dist[Sr][Sc] = 0;
while (!dq.empty()) {
auto [x, y] = dq.front(); dq.pop_front();
for (int d = 0; d < 4; ++d) {
int nx = x + dx[d], ny = y + dy[d];
if (in_bounds(nx, ny) && grid[nx][ny] == '.' && dist[nx][ny] > dist[x][y]) {
dist[nx][ny] = dist[x][y];
dq.push_front({nx, ny});
}
}
for (int i = max(0, x - N + 1); i <= min(R - N, x); ++i) {
for (int j = max(0, y - N + 1); j <= min(C - N, y); ++j) {
for (int a = i; a < i + N; ++a) {
for (int b = j; b < j + N; ++b) {
if (dist[a][b] > dist[x][y] + 1) {
dist[a][b] = dist[x][y] + 1;
dq.push_back({a, b});
}
}
}
}
}
}
cout << dist[Gr][Gc] << '\n';
return 0;
}
