//```// YF YUSUF
// #include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <queue>
#include <stack>
#include <cassert>
#include <climits>
#include <string>
#include <cstdlib>
#include <random>
#include <iomanip>
#include <ctime>
using namespace std;
#ifdef YF_CHECK
bool LOCAL = 1;
#else
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("O3")
bool LOCAL = 0;
#endif
using i128 = __int128;
using ll = int;
using ld = long double;
using vll = vector <ll>;
using mll = map <ll,ll>;
using pll = pair <ll,ll>;
using vvl = vector <vll>;
using vpll = vector <pll>;
template<class T>T MIN(T&a,T b){a=min(a,b);return a;}
template<class T>T MAX(T&a,T b){a=max(a,b);return a;}
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define sgr v+v+1,(tl+tr)/2+1,tr
#define sgl v+v,tl,(tl+tr)/2
#define pb push_back
#define ins insert
#define S second
#define F first
mt19937_64 MT(time(0));
ll BP(ll a,ll b,ll mod=1e9+7){
if(b==0)return 1;
ll q=BP(a,b/2,mod);
return ((q*q)%mod*(b%2?a:1ll))%mod;
}
ll f(ll x){return x*(x+1)/2;}
ll dup(ll a,ll b){return (a+b-1)/b;}
ll lcm(ll a,ll b){return a/__gcd(a,b)*b;}
ll invf(ll x){return (-1+sqrt(1+8*x))/2;}
ll lg(ll x){return (x ? 63 - __builtin_clzll(x) : -1);}
const ll mod=998244353;
const ll INF=1e18;
const ll inf=1e9+7;
const ll N =4e6+7;
int r, c, n;
bool check(ll i,ll j){
return ((1 <= i && i <= r) && (1 <= j && j <= c));
}
ll dx[] = {-1, 0, 1, 0,-1,-1, 1, 1};
ll dy[] = { 0,-1, 0, 1,-1, 1,-1, 1};
bool less_pair(pll a, pll b){
if(a.F != b.F) return a.F < b.F;
else return a.S > b.S;
}
void YF_MAIN(ll TEST){
ll x1,x2,y1,y2;
cin>>r>>c>>n>>x1>>y1>>x2>>y2;
char a[r+2][c+2]{};
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
cin>>a[i][j];
}
}
deque <pll> q;
vector<vpll> d(r+2, vpll(c+2, {inf, 0}));
d[x1][y1] = {0, 0};
q.push_front({x1, y1});
while(q.size()){
auto [i, j] = q.front();
// cout<<i<<" "<<j<<" "<<d[i][j].F<<" "<<d[i][j].S<<"\n";
q.pop_front();
if(d[i][j].S){
pll d_to = d[i][j];
d_to.S--;
for(int t=0; t<8; t++){
ll I = i + dx[t];
ll J = j + dy[t];
if(!check(I, J))continue;
if(less_pair(d_to, d[I][J])){
d[I][J] = d_to;
q.push_back({I, J});
}
}
}
else{
for(int t=0; t<4; t++){
ll I = i + dx[t];
ll J = j + dy[t];
if(!check(I, J))continue;
if(a[I][J] == '.'){
if(less_pair(d[i][j], d[I][J])){
d[I][J] = d[i][j];
q.push_front({I, J});
}
}
else{
pll d_to = {d[i][j].F + 1, n-1};
if(less_pair(d_to, d[I][J])){
d[I][J] = d_to;
q.push_back({I, J});
}
}
}
}
}
cout<<d[x2][y2].F;
}
const bool TECT=0;
const bool FLSH=1;
const ll SN=1e0 + 7; ll SM[SN];
const ll FN=1e0 + 7; ll FACT[FN], inv[FN], FMOD=inf;
ll PER(ll n,ll k){return FACT[n] *inv[n-k]%FMOD;}
ll CNK(ll n,ll k){return PER(n,k)*inv[k ]%FMOD;}
void BEFORE(){
for(ll i=2;i<SN;i++){
if(SM[i])continue;
for(ll j=i;j<SN;j+=i)
MAX(SM[j],i);
}
FACT[0]=inv[0]=1;
for(int i=1;i<FN;i++){
FACT[i]=FACT[i-1]*i%FMOD;
inv[i]=BP(FACT[i],FMOD-2,FMOD);
}
}
signed main(){
// freopen(("input.txt"),"r",stdin);freopen(("output.txt"),"w",stdout);
if(FLSH){
ios_base::sync_with_stdio(0);
cout.setf(ios::fixed);
cout.precision(0);
cout.tie(0);
cin.tie(0);
}
cout<<(0 && LOCAL ? "\nYF_OUTPUT:\n\n" : "");
int TEST=1;
if(TECT)
cin>>TEST;
BEFORE();
for(int T=1;T<=TEST;T++){
// cout<<"Case "<<T<<": ";
YF_MAIN(T);
cout<<(T==TEST ? "" : "\n");
}
return 0;
}
// YF YUSUF ```
