#include<bits/stdc++.h>
using namespace std;
int nbLig,nbCol,tailleMouv,ligDeb,colDeb,ligFin,colFin,dist;
vector<pair<int,int>> adja;
vector<bool> temp;
vector<string> val;
vector<vector<bool>> dv,dejaMur;
vector<pair<int,int>> frontiere,nouv,mur;
string mot;
void propage(int lig,int col,int gratos) {
if (lig>=1 and lig<=nbLig and col>=1 and col<=nbCol and (gratos==1 or (val[lig][col]=='.' and dv[lig][col]==false))) {
dv[lig][col]=true;
nouv.push_back({lig,col});
for (auto a:adja) {
propage(lig+a.first,col+a.second,0);
}
}
}
void testMur(int lig,int col) {
if (lig>=1 and lig<=nbLig and col>=1 and col<=nbCol and dv[lig][col]==false and dejaMur[lig][col]==false) {
dejaMur[lig][col]=true;
mur.push_back({lig,col});
}
}
void etend(int lig,int col,int direc,int rest) {
if (lig>=1 and lig<=nbLig and col>=1 and col<=nbCol and dv[lig][col]==false and rest>0) {
dv[lig][col]=true;
mur.push_back({lig,col});
etend(lig+adja[direc].first,col+adja[direc].second,direc,rest-1);
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
adja={{-1,0},{0,1},{1,0},{0,-1}};
cin>>nbLig>>nbCol>>tailleMouv;
cin>>ligDeb>>colDeb>>ligFin>>colFin;
for (int j=0;j<=nbCol+1;j++) {
temp.push_back(false);
}
for (int i=0;i<=nbLig+1;i++) {
dv.push_back(temp);
dejaMur.push_back(temp);
}
val.push_back("");
for (int i=1;i<=nbLig;i++) {
cin>>mot;
val.push_back(" "+mot);
}
propage(ligDeb,colDeb,1);
int lig,col,nbMur;
while (dv[ligFin][colFin]==false) {
frontiere=nouv;
nouv.clear();
mur.clear();
for (auto s:frontiere) {
for (auto a:adja) {
testMur(s.first+a.first,s.second+a.second);
}
}
nbMur=mur.size();
for (int i=0;i<nbMur;i++) {
lig=mur[i].first;
col=mur[i].second;
etend(lig,col-1,3,tailleMouv-1);
etend(lig,col+1,1,tailleMouv-1);
}
nbMur=mur.size();
for (int i=0;i<nbMur;i++) {
lig=mur[i].first;
col=mur[i].second;
etend(lig-1,col,0,tailleMouv-1);
etend(lig+1,col,2,tailleMouv-1);
}
nbMur=mur.size();
for (int i=0;i<nbMur;i++) {
lig=mur[i].first;
col=mur[i].second;
propage(lig,col,1);
}
/*for (auto s:nouv) {
cout<<s.first<<" "<<s.second<<endl;
}
cout<<endl;*/
dist++;
}
cout<<dist<<endl;
}
