#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long ll;
#define st first
#define nd second
#define f(a, c, b) for (int a = c; b > a; a++)
#define pb push_back
#define all(a) a.begin(), a.end()
#define sz(a) int(a.size())
#define int ll
#define DUZO 1000000000000000000
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
int n, m, k;
int ys, xs;
int yk, xk;
vvi a;
vvi o;
vector<pii> otoczka;
vector<pii> ruchy = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
vector<pii> skos = {{1, 1}, {1, -1}, {-1, 1}, {-1, -1}, {1, 0}, {-1, 0}, {0, 1}, {0, -1}};
int aktl_wnk = 0;
bool wolne(int y, int x) {
if (min(y, x) < 0) return false;
if (y >= n || x >= m) return false;
if (o[y][x]) return false;
return (!(a[y][x]));
}
bool zajete(int y, int x) {
if (min(y, x) < 0) return false;
if (y >= n || x >= m) return false;
if (o[y][x]) return false;
return (a[y][x]);
}
bool nie_odw(int y, int x) {
if (min(y, x) < 0) return false;
if (y >= n || x >= m) return false;
if (o[y][x]) return false;
return true;
}
void nowa_otoczka() {
aktl_wnk++;
vector<pii> no;
for (auto [y, x]: otoczka) {
for (pii ele: ruchy) {
int ny = y + ele.st;
int nx = x + ele.nd;
if (ny == yk && nx == xk) {
cout << aktl_wnk;
exit(0);
}
if (nie_odw(ny, nx)) {
o[ny][nx] = 1;
a[ny][nx] = 0;
no.pb({ny, nx});
}
}
}
otoczka = no;
/*cout << "otoczka po noramalnym rozszerzeniu:\n";
for (pii ele: otoczka) {
cout << ele.st << " " << ele.nd << "\n";
}
cout << "\n";*/
f(i, 1, k) {
vector<pii> no;
for (auto [y, x]: otoczka) {
//cout << "jestem w " << y << " " << x << "\n";
for (pii ele: skos) {
int ny = y + ele.st;
int nx = x + ele.nd;
if (ny == yk && xk == nx) {
cout << aktl_wnk << "\n";
exit(0);
}
if (nie_odw(ny, nx)) {
//cout << "moje czystki przetrwal kandydat " << ny << " " << nx << "\n";
o[ny][nx] = 1;
a[ny][nx] = 1;
no.pb({ny, nx});
}
}
//cout << "\n";
}
otoczka = no;
}
}
void bfs() { //majac do dyspozycji otoczke
int ind = 0;
while (sz(otoczka) > ind) {
pii p = otoczka[ind];
int y = p.st;
int x = p.nd;
if (y == yk && x == xk) {
cout << aktl_wnk << "\n";
exit(0);
}
ind++;
o[y][x] = 1;
for (pii ele: ruchy) {
int ny = y + ele.st;
int nx = x + ele.nd;
if (!wolne(ny, nx)) continue;
o[ny][nx] = 1;
otoczka.pb({ny, nx});
}
}
vector<pii> no;
for (auto [y, x]: otoczka) {
for (pii ele: ruchy) {
int ny = y + ele.st;
int nx = x + ele.nd;
if (zajete(ny, nx)) {no.pb({y, x}); break;}
}
}
otoczka = no;
}
void solve() {
cin >> n >> m >> k >> ys >> xs >> yk >> xk;
ys--;
xs--;
yk--;
xk--;
a.resize(n, vi(m));
o.resize(n, vi(m, 0));
f(i, 0, n) {
f(j,0, m) {
char z;
cin >> z;
if (z == '.') a[i][j] = 0;
else a[i][j] = 1;
}
}
otoczka.pb({ys, xs});
while (true) {
bfs();
/*cout << "po iteracji " << aktl_wnk << " nowa otoczka to:\n";
for (pii ele: otoczka) {
cout << ele.st << " " << ele.nd << "\n";
}
cout << "\n";*/
nowa_otoczka();
/*cout << "po rozszerzaniu zamieniamy to otoczke na:\n";
for (pii ele: otoczka) {
cout << ele.st << " " << ele.nd << "\n";
}
cout << "\n";*/
}
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int q = 1;
//cin >> q;
while (q--) solve();
return 0;
}
