#include <bits/stdc++.h>
using namespace std;
const int inf = 1e7;
const pair<int, int> deltas[4] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
vector<string> a;
vector<vector<int>> vis, dist;
int r, c, mini, minj, maxi, maxj, tt;
vector<pair<int, int>> listVis;
void dfs(int i, int j) {
listVis.emplace_back(i, j);
vis[i][j] = tt;
for (const auto& [di, dj] : deltas) {
if (i + di >= mini && i + di <= maxi && j + dj >= minj && j + dj <= maxj && vis[i + di][j + dj] < tt && dist[i + di][j + dj] >= dist[i][j]) {
dist[i + di][j + dj] = dist[i][j];
dfs(i + di, j + dj);
}
}
}
void solve() {
int n;
cin >> r >> c >> n;
int sr, sc, gr, gc;
cin >> sr >> sc >> gr >> gc;
--sr, --sc, --gr, --gc;
a.resize(r);
for (int i = 0; i < r; ++i) {
cin >> a[i];
}
vis.resize(r, vector<int>(c, -1));
dist.resize(r, vector<int>(c, inf));
vector<pair<int, int>> q[2], ext;
dist[sr][sc] = 0;
q[0].emplace_back(sr, sc);
int layer = 0;
tt = -1;
while (dist[gr][gc] == inf) {
while (!q[layer].empty()) {
auto [i, j] = q[layer].back();
q[layer].pop_back();
ext.emplace_back(i, j);
for (const auto& [di, dj] : deltas) {
int newi = i + di, newj = j + dj;
if (newi >= 0 && newi < r && newj >= 0 && newj < c && a[newi][newj] == '.' && dist[newi][newj] == inf) {
dist[newi][newj] = dist[i][j];
q[layer].emplace_back(newi, newj);
}
}
}
for (int iter = 0; iter < 4; ++iter) {
++tt;
sort(ext.begin(), ext.end());
if (iter == 0) {
// up
for (auto [i, j] : ext) {
mini = max(0, i - n), minj = max(0, j - n + 1);
maxi = min(r - 1, i - 1), maxj = min(c - 1, j + n - 1);
if (i - 1 >= 0 && vis[i - 1][j] < tt && dist[i - 1][j] > dist[i][j]) {
dist[i - 1][j] = dist[i][j] + 1;
dfs(i - 1, j);
}
}
} else if (iter == 1) {
// left
for (auto [j, i] : ext) {
i = -i;
mini = max(0, i - n + 1), minj = max(0, j - n);
maxi = min(r - 1, i + n - 1), maxj = min(c - 1, j - 1);
if (j - 1 >= 0 && vis[i][j - 1] < tt && dist[i][j - 1] > dist[i][j]) {
dist[i][j - 1] = dist[i][j] + 1;
dfs(i, j - 1);
}
}
} else if (iter == 2) {
// down
for (auto [i, j] : ext) {
i = -i, j = -j;
mini = max(0, i + 1), minj = max(0, j - n + 1);
maxi = min(r - 1, i + n), maxj = min(c - 1, j + n - 1);
if (i + 1 < r && vis[i + 1][j] < tt && dist[i + 1][j] > dist[i][j]) {
dist[i + 1][j] = dist[i][j] + 1;
dfs(i + 1, j);
}
}
} else {
// right
for (auto [j, i] : ext) {
j = -j;
mini = max(0, i - n + 1), minj = max(0, j + 1);
maxi = min(r - 1, i + n - 1), maxj = min(c - 1, j + n);
if (j + 1 < c && vis[i][j + 1] < tt && dist[i][j + 1] > dist[i][j]) {
dist[i][j + 1] = dist[i][j] + 1;
dfs(i, j + 1);
}
}
}
for (int i = 0; i < (int)ext.size(); ++i) {
ext[i].first = -ext[i].first;
swap(ext[i].first, ext[i].second);
}
}
ext.clear();
sort(listVis.begin(), listVis.end());
listVis.resize(unique(listVis.begin(), listVis.end()) - listVis.begin());
layer ^= 1;
swap(q[layer], listVis);
listVis.clear();
}
cout << dist[gr][gc] << '\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
int T = 1;
cin >> T;
while (T--) {
solve();
cerr << "-----------\n";
cout << "-----------\n";
}
#else
int T = 1;
// cin >> T;
while (T--) {
solve();
}
#endif
return 0;
}
