#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define Mp make_pair
#define sep ' '
#define endl '\n'
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define kill(res) cout << res << '\n', exit(0);
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 6e6 + 50;
const ll Mod = 1e9 + 7;
int R, C, n;
pii s, t;
string a[N];
struct cst{
int F = Mod, S, T;
};
vector<cst> cost[N];
bool ok(int x, int y){
return (0 <= min(x, y) && x < R && y < C);
}
int main(){
fast_io;
cin >> R >> C >> n >> s.F >> s.S >> t.F >> t.S;
s.F--; s.S--; t.F--; t.S--; n--; n = -n;
for(int i = 0; i < R; i++) cin >> a[i];
for(int i = 0; i < R; i++) cost[i].resize(C);
vector<pii> q0, q1;
q0.pb({s.F, s.S});
cost[s.F][s.S] = {0, 0, 0};
while(!q0.empty()){
for(int i = 0; i < q0.size(); i++){
auto [r, c] = q0[i];
auto [x, y, z] = cost[r][c];
if(y != 0){
if(ok(r+1, c) && x < cost[r+1][c].F){
cost[r+1][c] = {x, y+1, z};
q0.pb({r+1, c});
}
if(ok(r-1, c) && x < cost[r-1][c].F){
cost[r-1][c] = {x, y+1, z};
q0.pb({r-1, c});
}
}
}
for(int i = 0; i < q0.size(); i++){
auto [r, c] = q0[i];
auto [x, y, z] = cost[r][c];
if(z != 0){
if(ok(r, c+1) && x < cost[r][c+1].F){
cost[r][c+1] = {x, y, z+1};
q0.pb({r, c+1});
}
if(ok(r, c-1) && x < cost[r][c-1].F){
cost[r][c-1] = {x, y, z+1};
q0.pb({r, c-1});
}
}
}
for(int i = 0; i < q0.size(); i++){
auto [r, c] = q0[i];
auto [x, y, z] = cost[r][c];
if(ok(r+1, c)){
if(a[r+1][c] == '#'){
if(cost[r+1][c].F > x+1){
cost[r+1][c] = {x+1, n, n};
q1.pb({r+1, c});
}
}
else{
if(cost[r+1][c].F > x){
cost[r+1][c] = {x, 0, 0};
q0.pb({r+1, c});
}
}
}
if(ok(r-1, c)){
if(a[r-1][c] == '#'){
if(cost[r-1][c].F > x+1){
cost[r-1][c] = {x+1, n, n};
q1.pb({r-1, c});
}
}
else{
if(cost[r-1][c].F > x){
cost[r-1][c] = {x, 0, 0};
q0.pb({r-1, c});
}
}
}
if(ok(r, c+1)){
if(a[r][c+1] == '#'){
if(cost[r][c+1].F > x+1){
cost[r][c+1] = {x+1, n, n};
q1.pb({r, c+1});
}
}
else{
if(cost[r][c+1].F > x){
cost[r][c+1] = {x, 0, 0};
q0.pb({r, c+1});
}
}
}
if(ok(r, c-1)){
if(a[r][c-1] == '#'){
if(cost[r][c-1].F > x+1){
cost[r][c-1] = {x+1, n, n};
q1.pb({r, c-1});
}
}
else{
if(cost[r][c-1].F > x){
cost[r][c-1] = {x, 0, 0};
q0.pb({r, c-1});
}
}
}
}
q0.clear();
swap(q0, q1);
}
cout << cost[t.F][t.S].F;
}
