// 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;
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>> vis(R, std::vector<int>(C));
std::vector<std::vector<int>> dis(R, std::vector<int>(C, R * C));
std::deque<std::pair<int, int>> deq;
dis[SX][SY] = 0;
deq.emplace_back(SX, SY);
while (!deq.empty()) {
auto[x, y] = deq.front();
deq.pop_front();
if (vis[x][y]) {
continue;
}
vis[x][y] = true;
debug(x, y, dis[x][y]);
for (int d = 0; d < 4; ++d) {
int nx = x + dx[d];
int ny = y + dy[d];
if (0 <= nx && nx < R && 0 <= ny && ny < C) {
if (A[nx][ny] == '.') {
if (chmin(dis[nx][ny], dis[x][y])) {
deq.emplace_front(nx, ny);
}
}
}
}
for (int DX = -N; DX <= N; ++DX) {
for (int DY = -N; DY <= N; ++DY) {
if (std::abs(DX) == N && std::abs(DY) == N) {
continue;
}
int X = x + DX;
int Y = y + DY;
if (0 <= X && X < R && 0 <= Y && Y < C) {
if (chmin(dis[X][Y], dis[x][y] + 1)) {
deq.emplace_back(X, Y);
}
}
}
}
}
std::cout << dis[GX][GY] << '\n';
return 0;
}
