#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1000'000'000'000'000'000LL;
const int II = 2'000'000'000;
const ll M = 1000'000'007LL;
const int N = 6'000'007;
int tab[N];
vector<pair<int, int>> roza;
int n, m;
int dis[N];
void DoRoza()
{
for(int i = -1; i <= 1; ++i)
for(int j = -1; j <= 1; ++j)
if(i != 0 || j != 0)
roza.pb(make_pair(i, j));
}
void BFS(int s1, int s2, int k)
{
queue<int> q0, q1;
for(int i = 1; i <= n * m; ++i) dis[i] = II;
int v, i, j;
v = (s1 - 1) * m + s2;
dis[v] = tab[v];
q0.push(v);
while((int)q0.size() + (int)q1.size() > 0)
{
if((int)q0.size() == 0 || ((int)q1.size() > 0 && dis[q1.front()] <= dis[q0.front()]))
{v = q1.front(); q1.pop();}
else
{v = q0.front(); q0.pop();}
i = (v + m - 1) / m; j = v - (i - 1) * m;
//if(dis[v] == 0)
//cout << "D: " << "{ " << i << " " << j << " }: " << dis[v] << "\n";
for(int l = 0; l < (int)roza.size(); ++l)
{
int ni = i + roza[l].st, nj = j + roza[l].nd;
int ne = (ni - 1) * m + nj;
if(ni < 1 || ni > n || nj < 1 || nj > m) continue;
if((ni == i || nj == j) && dis[v] % k == 0 && !tab[ne] && dis[v] < dis[ne])
{
//cout << "E0: " << "{ " << i << " " << j << " } -> { " << ni << " " << nj << " }\n";
dis[ne] = dis[v];
q0.push(ne);
}else if(dis[v] + 1 < dis[ne] && (dis[v] % k != 0 || (ni == i || nj == j)))
{
dis[ne] = dis[v] + 1;
q1.push(ne);
}
}
}
}
void Solve()
{
int k, s1, s2, e1, e2;
string s;
cin >> n >> m >> k;
cin >> s1 >> s2;
cin >> e1 >> e2;
for(int i = 1; i <= n; ++i)
{
cin >> s;
for(int j = 1; j <= m; ++j)
if(s[j - 1] == '#') tab[(i - 1) * m + j] = 1;
}
BFS(s1, s2, k);
int ans = dis[(e1 - 1) * m + e2];
ans = (ans + k - 1) / k;
cout << ans << "\n";
}
int main()
{
DoRoza();
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//int t; cin >> t;
//while(t--)
Solve();
return 0;
}
