// File maze.cpp created on 29.09.2025 at 10:19:41
#include <bits/stdc++.h>
using i64 = long long;
#ifdef DEBUG
#include "/home/ahmetalp/Desktop/Workplace/debug.h"
#else
#define debug(...) void(23)
#endif
constexpr int dx[] = {0, +1, 0, -1};
constexpr int dy[] = {+1, 0, -1, 0};
template<typename T>
bool chmin(T& a, T b) {
if (a > b) {
a = b;
return true;
}
return false;
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int R, C, N;
std::cin >> R >> C >> N;
auto in = [&](int x, int y) -> bool {
return 0 <= x && x < R && 0 <= y && y < C;
};
int SX, SY, GX, GY;
std::cin >> SX >> SY >> GX >> GY;
--SX, --SY, --GX, --GY;
std::vector<std::string> A(R);
for (int i = 0; i < R; ++i) {
std::cin >> A[i];
}
std::vector<std::vector<int>> dis(R, std::vector<int>(C, R * C));
std::vector<std::pair<int, int>> que;
dis[SX][SY] = 0;
que.emplace_back(SX, SY);
for (int i = 0; i < int(que.size()); ++i) {
auto[x, y] = que[i];
for (int d = 0; d < 4; ++d) {
int nx = x + dx[d];
int ny = y + dy[d];
if (in(nx, ny) && A[nx][ny] == '.' && chmin(dis[nx][ny], 0)) {
que.emplace_back(nx, ny);
}
}
}
for (int diss = 1; !que.empty(); ++diss) {
#ifdef DEBUG
debug(que);
std::vector<std::vector<int>> vis(R, std::vector<int>(C));
for (auto[x, y] : que) {
vis[x][y] = true;
}
for (int i = 0; i < R; ++i) {
for (int j = 0; j < C; ++j) {
std::cerr << vis[i][j] << " \n"[j == C - 1];
}
}
#endif
std::vector<std::pair<int, int>> guys, nque;
for (auto[x, y] : que) {
for (int d = 0; d < 4; ++d) {
int nx = x + dx[d];
int ny = y + dy[d];
if (in(nx, ny) && chmin(dis[nx][ny], diss)) {
guys.emplace_back(nx, ny);
nque.emplace_back(nx, ny);
}
}
}
for (int n = 2; n <= N; ++n) {
std::vector<std::pair<int, int>> nguys;
for (auto[x, y] : guys) {
for (int d : {0, 2}) {
int nx = x + dx[d];
int ny = y + dy[d];
if (in(nx, ny) && chmin(dis[nx][ny], diss)) {
nguys.emplace_back(nx, ny);
nque.emplace_back(nx, ny);
}
}
}
guys = std::move(nguys);
}
guys = nque;
for (int n = 2; n <= N; ++n) {
std::vector<std::pair<int, int>> nguys;
for (auto[x, y] : guys) {
for (int d : {1, 3}) {
int nx = x + dx[d];
int ny = y + dy[d];
if (in(nx, ny) && chmin(dis[nx][ny], diss)) {
nguys.emplace_back(nx, ny);
nque.emplace_back(nx, ny);
}
}
}
guys = std::move(nguys);
}
que = std::move(nque);
for (int i = 0; i < int(que.size()); ++i) {
auto[x, y] = que[i];
for (int d = 0; d < 4; ++d) {
int nx = x + dx[d];
int ny = y + dy[d];
if (in(nx, ny) && A[nx][ny] == '.' && chmin(dis[nx][ny], diss)) {
que.emplace_back(nx, ny);
}
}
}
}
std::cout << dis[GX][GY] << '\n';
return 0;
}
