#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define l(a, b, i) for (ll i = a; i < b; i++)
#define rl(a, b, i) for (ll i = a; i >= b; i--)
#define vpair vector<pair<ll, ll>>
#define inf LLONG_MAX
#define ninf LLONG_MIN
ll N, H, W, Sr, Sc, Gr, Gc;
vector<vector<char>> grid;
//vector<vector<bool>> visited;
vector<vector<bool>> stamped;
vector<vector<ll>> dist;
ll dr[4] = {-1, 1, 0, 0};
ll dc[4] = {0, 0, -1, 1};
void dijkstra(ll start_r, ll start_c) {
//visited.assign(H + 1, vector<bool> (W + 1, false));
stamped.assign(H - N + 2, vector<bool> (W - N + 2, false));
dist.assign(H + 1, vector<ll> (W + 1, inf));
priority_queue<pair<ll, pair<ll, ll>>, vector<pair<ll, pair<ll, ll>>>, greater<>> pq;
dist[start_r][start_c] = 0;
pq.push({0, {start_r, start_c}});
while (!pq.empty()) {
ll r = pq.top().second.first;
ll c = pq.top().second.second;
ll curdist = pq.top().first;
pq.pop();
//if (!visited[r][c]) {
//visited[r][c] = true;
l(0, 4, i) {
ll nr = r + dr[i];
ll nc = c + dc[i];
if (nr < 1 || nr > H || nc < 1 || nc > W) continue;
//if (grid[nr][nc] == '#') continue;
//ll w = 0;
if (grid[nr][nc] == '#') {
// Basically là range của các square N x N mà có thể cover được grid[nr][nc]
ll r1 = max(1LL, nr - N + 1);
ll c1 = max(1LL, nc - N + 1);
ll r2 = min(nr, H - N + 1);
ll c2 = min(nc, W - N + 1);
l(r1, r2 + 1, sr) {
l(c1, c2 + 1, sc) {
if (stamped[sr][sc]) continue;
stamped[sr][sc] = true;
l(sr, sr + N, i) {
l(sc, sc + N, j) {
if (i < 1 || i > H || j < 1 || j > W) continue;
if (dist[i][j] > curdist + 1) {
dist[i][j] = curdist + 1; // tất cả các ô ở trong square mình vừa stamp đều sẽ reachable không mất phí nữa :D
pq.push({dist[i][j], {i, j}});
}
}
}
}
}
}
else { // nếu là ô trắng thì đi k mất tí phí nào ^^
if (dist[nr][nc] > curdist) {
dist[nr][nc] = curdist;
pq.push({dist[nr][nc], {nr, nc}});
}
}
}
//}
}
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> H >> W >> N >> Sr >> Sc >> Gr >> Gc;
grid.resize(H + 1, vector<char>(W + 1));
l(1, H + 1, r) {
string A; cin >> A;
l(0, W, c) grid[r][c + 1] = A[c];
}
dijkstra(Sr, Sc);
cout << dist[Gr][Gc];
}
