#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
#include <queue>
typedef long long llong;
const int MAXN = 6000000 + 10;
const int INF = 1e9;
int r, c, n;
int sRow, sCol;
int eRow, eCol;
std::pair <int,int> delta[] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
std::deque <std::pair <int,int>> dq;
std::vector <int> dist[MAXN];
std::string t[MAXN];
bool isOutside(int row, int col)
{
return row == 0 || row == r + 1 || col == 0 || col == c + 1;
}
void solve()
{
for (int i = 1 ; i <= r ; ++i)
{
std::fill(dist[i].begin(), dist[i].end(), INF);
}
dq.push_back({sRow, sCol});
dist[sRow][sCol] = 0;
while (!dq.empty())
{
auto [row, col] = dq.front();
dq.pop_front();
if (row == eRow && col == eCol)
{
std::cout << dist[row][col] << '\n';
break;
}
for (const auto &[dx, dy] : delta)
{
if (isOutside(row + dx, col + dy) || dist[row + dx][col + dy] <= dist[row][col])
{
continue;
}
if (t[row + dx][col + dy] == '.')
{
dist[row + dx][col + dy] = dist[row][col];
dq.push_front({row + dx, col + dy});
}
}
if (abs(row - eRow) <= n && abs(col - eCol) <= n && dist[eRow][eCol] > dist[row][col])
{
dist[eRow][eCol] = dist[row][col] + 1;
dq.push_back({eRow, eCol});
}
for (int i = std::max(1, col - n + 1) ; i <= std::min(c, col + n - 1) ; ++i)
{
int prevR = std::max(1, row - n);
int nextR = std::min(r, row + n);
if (dist[prevR][i] > dist[row][col] + 1)
{
dist[prevR][i] = dist[row][col] + 1;
dq.push_back({prevR, i});
}
if (dist[nextR][i] > dist[row][col] + 1)
{
dist[nextR][i] = dist[row][col] + 1;
dq.push_back({nextR, i});
}
}
for (int i = std::max(1, row - n + 1) ; i <= std::min(r, row + n - 1) ; ++i)
{
int prevC = std::max(1, col - n);
int nextC = std::min(c, col + n);
if (dist[i][prevC] > dist[row][col] + 1)
{
dist[i][prevC] = dist[row][col] + 1;
dq.push_back({i, prevC});
}
if (dist[i][nextC] > dist[row][col] + 1)
{
dist[i][nextC] = dist[row][col] + 1;
dq.push_back({i, nextC});
}
}
}
}
void input()
{
std::cin >> r >> c >> n;
std::cin >> sRow >> sCol;
std::cin >> eRow >> eCol;
for (int i = 1 ; i <= r ; ++i)
{
std::cin >> t[i];
t[i] = ' ' + t[i];
dist[i].resize(c + 1, INF);
}
}
void fastIOI()
{
std::ios_base :: sync_with_stdio(0);
std::cout.tie(nullptr);
std::cin.tie(nullptr);
}
int main()
{
fastIOI();
input();
solve();
return 0;
}
