#include <bits/stdc++.h>
using namespace std;
const int dx[] = {1, 0, -1, 0},
dy[] = {0, 1, 0, -1};
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
int r, c, n; cin >> r >> c >> n;
int Sr, Sc; cin >> Sr >> Sc;
int Gr, Gc; cin >> Gr >> Gc;
vector<vector<char>> a(r + 10, vector<char>(c + 10));
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) cin >> a[i][j];
}
auto in = [&](int x, int y) { return 1 <= x && x <= r && 1 <= y && y <= c; };
vector<vector<int>> f(r + 10, vector<int>(c + 10, 1'000'000'000));
auto getSquare = [&](int x, int y, int way, int type) {
vector<pair<int, int>> ret = {{x, y}};
for (int t = 0; t < 4; ++t) {
for (int i = 1; i < n; ++i) {
x += dx[way]; y += dy[way];
ret.push_back({x, y});
}
way = (way + type + 4) % 4;
}
return ret;
};
deque<pair<int, int>> q;
q.push_back({Sr, Sc});
f[Sr][Sc] = 0;
while (q.size()) {
auto [x, y] = q.front(); q.pop_front();
if (abs(Gr - x) <= n && abs(Gc - y) <= n) { f[Gr][Gc] = min(f[Gr][Gc], f[x][y] + 1); }
for (int t = 0; t < 4; ++t) {
int nX = x + dx[t], nY = y + dy[t];
if (!in(nX, nY) || a[nX][nY] == '#') continue;
if (f[nX][nY] > f[x][y]) {
f[nX][nY] = f[x][y];
q.push_front({nX, nY});
}
}
for (int t = 0; t < 4; ++t) {
int stX = x + dx[t], stY = y + dy[t];
for (int type = -1; type <= 1; type += 2) {
for (const auto& [nX, nY] : getSquare(stX, stY, t, type)) {
if (!in(nX, nY)) continue;
if (f[nX][nY] > f[x][y] + 1) {
f[nX][nY] = f[x][y] + 1;
q.push_back({nX, nY});
}
}
}
}
}
cout << f[Gr][Gc] << "\n";
}
