#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
#define int long long
#define fi first
#define se second
const int dx[4] = {0, -1, 1, 0}, dy[4] = {1, 0, 0, -1};
const int Dx[8] = {-1, 0, 1, -1, 1, -1, 0, 1}, Dy[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
const int inf = 1e9;
struct state {
int x, y, d1, d2;
};
bool cmp(pair<int, int> x, pair<int, int> y) { // is y better than x
if (y.first < x.first) return true;
if (y.first == x.first && y.second > x.second) return true;
return false;
};
void solve() {
int r, c, n, sr, sc, gr, gc;
cin >> r >> c >> n >> sr >> sc >> gr >> gc;
vector<vector<char>> a(r+1, vector<char> (c+1));
for (int i = 1; i <= r; i++) for (int j = 1; j <= c; j++) cin >> a[i][j];
vector<vector<pair<int, int>>> di(r+1, vector<pair<int, int>> (c+1, {inf, inf}));
vector<vector<bool>> vis(r+1, vector<bool> (c+1, 0));
deque<state> q;
q.push_back({sr, sc, 0, 0});
di[sr][sc] = {0, 0};
while (!q.empty()) {
auto [x, y, d1, d2] = q.front();
q.pop_front();
if (x == gr && y == gc) {
cout << d1 << '\n';
return;
}
if (di[x][y] != make_pair(d1, d2)) continue;
if (d2) {
for (int i = 0; i < 8; i++) {
int nx = x + Dx[i], ny = y + Dy[i];
if (nx < 1 || nx > r || ny < 1 || ny > c) continue;
if (cmp(di[nx][ny], make_pair(d1, d2-1))) {
di[nx][ny] = make_pair(d1, d2-1);
q.push_back({nx, ny, d1, d2-1});
}
}
} else {
for (int i = 0; i < 4; i++) {
int nx = x + dx[i], ny = y + dy[i];
if (nx < 1 || nx > r || ny < 1 || ny > c) continue;
if (a[nx][ny] == '#') {
if (cmp(di[nx][ny], make_pair(d1+1, n-1))) {
di[nx][ny] = make_pair(d1+1, n-1);
q.push_back({nx, ny, d1+1, n-1});
}
} else {
if (cmp(di[nx][ny], make_pair(d1, 0))) {
di[nx][ny] = make_pair(d1, 0);
q.push_front({nx, ny, d1, 0});
}
}
}
}
}
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int test = 1;
// cin >> test;
while (test--) solve();
}
