#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long int lld;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define trav(a,v) for(auto a:v)
int r,c,n;
int valid(int x, int y){
if(x>=0 && x<r && y>=0 && y<c)return true;
return false;
}
void solve(){
cin>>r>>c>>n;
int sx,sy;
cin>>sx>>sy;
sx--;sy--;
int gx,gy;
cin>>gx>>gy;
gx--;gy--;
vector<string> V(r);
rep(i,0,r)cin>>V[i];
deque<tuple<int,int,int> >q;
vector<vector<int> >dist(r);
rep(i,0,r)dist[i].resize(c,1000000000);
dist[sx][sy]=0;
q.push_back({sx,sy,0});
while(!q.empty()){
auto [x,y,d]=q.front();
q.pop_front();
if(d>dist[x][y])continue;
if(V[x][y]=='.'){
rep(dx,x-1,x+2){
rep(dy,y-1,y+2){
if(abs(dx-x)+abs(dy-y)==1){
if(valid(dx,dy)){
if(dist[dx][dy]>d){
dist[dx][dy]=d;
q.push_front({dx,dy,d});
}
}
}
}
}
}
rep(dx,x-n,x+n+1){
rep(dy,y-n,y+n+1){
if(abs(dx-x)+abs(dy-y)<=2*n-1){
if(valid(dx,dy)){
if(dist[dx][dy]>d+1){
dist[dx][dy]=d+1;
q.push_back({dx,dy,d+1});
}
}
}
}
}
}
cout<<dist[gx][gy]<<"\n";
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
int tt=1;
//cin>>tt;
while(tt--){
solve();
}
}
