/*
Mayoeba Yabureru
*/
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
void solve() {
int r, c, n, sx, sy, fx, fy;
cin >> r >> c >> n >> sx >> sy >> fx >> fy;
vector a(r + 1, vector(c + 1, ' '));
for (int i = 1; i <= r; i ++) {
for (int j = 1; j <= c; j ++) cin >> a[i][j];
}
queue<vector<int>> last;
vector dis(r + 1, vector(c + 1, 100000000)), diss = dis;
dis[sx][sy] = 0;
last.push({sx, sy});
vector dx = {-1, 1, 0, 0}, dy = {0, 0, 1, -1};
int num = 0;
while (dis[fx][fy] == 1e8) {
queue<vector<int>> current;
while (last.size()) {
auto v = last.front();
current.push(v);
last.pop();
int x = v[0], y = v[1];
diss[x][y] = 0;
for (int i = 0; i < 4; i ++) {
int nx = x + dx[i], ny = y + dy[i];
if (nx <= 0 || ny <= 0 || nx > r || ny > c) continue;
if (dis[nx][ny] > dis[x][y] && a[nx][ny] == '.') {
dis[nx][ny] = dis[x][y];
last.push({nx, ny});
}
}
}
while (current.size()) {
auto v = current.front();
current.pop();
int x = v[0], y = v[1];
if (dis[x][y] == num + 1) last.push(v);
if (diss[x][y] == n + n - 1) continue;
for (int i = 0; i < 4; i ++) {
int nx = x + dx[i], ny = y + dy[i];
if (nx <= 0 || ny <= 0 || nx > r || ny > c) continue;
if (diss[nx][ny] > diss[x][y] + 1) {
diss[nx][ny] = diss[x][y] + 1;
dis[nx][ny] = num + 1;
current.push({nx, ny});
}
}
}
num ++;
}
cout << dis[fx][fy] << endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int T = 1;
for (int I = 1; I <= T; I++) {
solve();
}
}
