#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
using ull = unsigned long long;
#define X first
#define Y second
#define SZ(x) int(x.size())
#define all(x) x.begin(), x.end()
#define mins(a,b) (a = min(a,b))
#define maxs(a,b) (a = max(a,b))
#define pb push_back
#define Mp make_pair
#define lc id<<1
#define rc lc|1
#define mid ((l+r)/2)
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll INF = 1e9 + 23;
int R, C, N, sr, sc, er, ec;
vector<vector<char>> a;
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};
vector<vector<int>> dis;
bool in(int x, int y) {
return 0<=x&&x<R && 0<=y&&y<C;
}
void BFS() {
queue<pair<pii, pii>> q1, q2;
dis[sr][sc] = 0;
q1.push(Mp(Mp(sr, sc), Mp(0, 0)));
while(SZ(q1)+SZ(q2)) {
while(SZ(q1)) {
auto [x, y] = q1.front().X;
q1.pop();
for(int d=0; d<4; d++) {
int xx = x+dx[d], yy = y+dy[d];
if(!in(xx, yy)) continue;
if(a[xx][yy] == '.') {
if(dis[xx][yy]>dis[x][y]) {
dis[xx][yy] = dis[x][y];
q1.push(Mp(Mp(xx, yy), Mp(0, 0)));
}
}
else {
if(dis[xx][yy]>dis[x][y]+1) {
dis[xx][yy] = dis[x][y]+1;
q2.push(Mp(Mp(xx, yy), Mp(N-1, N-1)));
}
}
}
}
while(SZ(q2)) {
auto [x, y] = q2.front().X;
auto [xd, yd] = q2.front().Y;
q2.pop();
if(min(xd, yd) == 0) q1.push(Mp(Mp(x, y), Mp(0, 0)));
for(int d=0; d<4; d++) {
int xx = x+dx[d], yy = y+dy[d];
int xxd = xd - (dx[d]!=0), yyd = yd - (dy[d]!=0);
if(!in(xx, yy) || xxd < 0 || yyd < 0) continue;
if(dis[xx][yy]>dis[x][y]) {
dis[xx][yy] = dis[x][y];
q2.push(Mp(Mp(xx, yy), Mp(xxd, yyd)));
}
}
}
}
}
void Main() {
cin >> R >> C >> N;
cin >> sr >> sc >> er >> ec; sr--; sc--; er--; ec--;
a = vector<vector<char>>(R, vector<char>(C));
dis = vector<vector<int>>(R, vector<int>(C, INF));
for(int r=0; r<R; r++)
for(int c=0; c<C; c++)
cin >> a[r][c];
BFS();
cout << dis[er][ec] << '\n';
}
int32_t main() {
cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
int T = 1;
// cin >> T;
while(T--) Main();
return 0;
}
