#include <bits/stdc++.h>
#include <experimental/random>
#include <random>
//#include <ext/pb_ds/assoc_container.hpp>
//using namespace __gnu_pbds;
using namespace std;
using ld = long double;
using ll = long long;
const int INF = 1e9, MOD = 1e9 + 7;
void solve();
signed main() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int q = 1;
//cin >> q;
while (q--) {
solve();
}
}
vector<pair<int, int>> cord = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
void solve() {
int r, c, n;
cin >> r >> c >> n;
int sr, sc, gr, gc;
cin >> sr >> sc >> gr >> gc;
sr--, sc--, gr--, gc--;
vector<vector<char>> a(r, vector<char>(c));
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
cin >> a[i][j];
}
}
if (r > c) {
swap(r, c);
swap(sr, sc); swap(gr, gc);
vector<vector<char>> nw(r, vector<char>(c));
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
nw[i][j] = a[j][i];
}
}
a = nw;
}
if (n >= r) {
queue<pair<int, int>> bfs;
bfs.emplace(sr, sc);
vector<vector<int>> used(r, vector<int>(c));
used[sr][sc] = 1;
int mn = sc, mx = sc;
while (!empty(bfs)) {
auto [i, j] = bfs.front();
bfs.pop();
mn = min(mn, j); mx = max(mx, j);
for (auto [fx, fy] : cord) {
int x = i + fx, y = j + fy;
if (x < 0 || y < 0 || x == r || y == c || a[x][y] == '#') {
continue;
}
if (used[x][y]) {
continue;
}
used[x][y] = 1;
bfs.emplace(x, y);
}
}
int col = 0;
int lf = sc + 1, rf = sc - 1;
while (!used[gr][gc]) {
int nwl = max(0, mn - n), nwr = min(c - 1, mx + n);
for (int i = 0; i < r; i++) {
for (int j = nwl; j < lf; j++) {
used[i][j] = 1;
}
for (int j = rf + 1; j <= nwr; j++) {
used[i][j] = 1;
}
}
col++;
lf = nwl, rf = nwr;
for (int i = 0; i < r; i++) {
bfs.emplace(i, lf);
bfs.emplace(i, rf);
}
while (!empty(bfs)) {
auto [i, j] = bfs.front();
bfs.pop();
mn = min(mn, j); mx = max(mx, j);
for (auto [fx, fy] : cord) {
int x = i + fx, y = j + fy;
if (x < 0 || y < 0 || x == r || y == c || a[x][y] == '#') {
continue;
}
if (used[x][y]) {
continue;
}
used[x][y] = 1;
bfs.emplace(x, y);
}
}
}
cout << col;
return;
}
vector<vector<int>> used(r, vector<int>(c));
vector<set<int>> hv(r);
for (int i = 0; i < r; i++) {
for (int j = 0; j < c; j++) {
hv[i].insert(j);
}
}
int col = 0;
queue<pair<int, int>> bfs;
bfs.emplace(sr, sc);
used[sr][sc] = 1;
hv[sr].erase(sc);
vector<pair<int, int>> elems;
while (!bfs.empty()) {
auto [i, j] = bfs.front();
bfs.pop();
elems.emplace_back(i, j);
for (auto [fx, fy] : cord) {
int x = i + fx, y = j + fy;
if (x < 0 || y < 0 || x == r || y == c || a[x][y] == '#') {
continue;
}
if (used[x][y]) {
continue;
}
used[x][y] = 1;
hv[x].erase(y);
bfs.emplace(x, y);
}
}
while (!used[gr][gc]) {
for (auto [x, y] : elems) {
for (int i = max(0, x - n); i <= min(r - 1, x + n); i++) {
int lf = max(0, y - n), rf = min(c - 1, y + n);
if (abs(x - i) == n) {
lf = max(0, y - n + 1), rf = min(c - 1, y + n - 1);
}
auto it = hv[i].lower_bound(lf);
vector<int> del;
while (it != hv[i].end() && *it <= rf) {
del.push_back(*it);
used[i][*it] = 1;
bfs.emplace(i, *it);
it++;
}
for (auto j : del) {
hv[i].erase(j);
}
}
}
vector<pair<int, int>> nw;
while (!bfs.empty()) {
auto [i, j] = bfs.front();
bfs.pop();
nw.emplace_back(i, j);
for (auto [fx, fy] : cord) {
int x = i + fx, y = j + fy;
if (x < 0 || y < 0 || x == r || y == c || a[x][y] == '#') {
continue;
}
if (used[x][y]) {
continue;
}
used[x][y] = 1;
hv[x].erase(y);
bfs.emplace(x, y);
}
}
elems = nw;
col++;
}
cout << col;
}
