#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#define pb push_back
#define F first
#define pii pair<int,int>
#define all(a) a.begin(),a.end()
#define S second
#define sz(a) (int)a.size()
#define rep(i , a , b) for(int i = (a) ; i <= (b) ; i++)
#define per(i , a , b) for(int i = (a) ; i >= (b) ; i--)
#define ld long double
#define int long long
using namespace std ;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 6e6+20 , maxm = 2e4 + 220, sq = 500 , inf = 1e18+10 , mod =998244353 ;
int r , c , n ;
bool mark[maxn] ;
char a[maxn] , ok[maxn] ;
vector <int> vec[maxn] , vec2[maxn] ;
int dx[] = {1 , -1 , 0 , 0} , dy[] = {0 , 0 , -1 , 1} ;
int f(int i ,int j){
return (i-1)*c + j-1 ;
}
pii g(int x){
return {x/c +1, x%c+1} ;
}
signed main(){
ios_base::sync_with_stdio(false) ; cin.tie(0) ;
cin >> r >> c >> n ;
int a1 , a2 , b1 , b2 ;
cin >> a1 >> a2 ;
cin>> b1 >> b2 ;
rep(i ,1, r){
rep(j ,1 ,c){
cin >> a[f(i,j)];
}
}
vector <int> nw ;
nw.pb(f(a1,a2));
rep(sp , 0 , r*c){
queue <int> q ;
for(int x : nw){
q.push(x) ;
mark[x] = 1;
}
while(sz(q)){
int v = q.front() ;q.pop() ;
int vi = g(v).F , vj = g(v).S ;
rep(i , 0 , 3){
int ui = vi+dx[i] , uj = vj+dy[i] ;
if(ui <= 0 || ui > r || uj <= 0 || uj > c || a[f(ui , uj)] == '#' || mark[f(ui , uj)] == 1){
continue ;
}
mark[f(ui , uj)] = 1;
nw.pb(f(ui, uj));
q.push(f(ui,uj));
}
}
// for(int x : nw){
// cout << x << " " ;
// }
// cout << "\n";
vector <int> nw2 , ro ;
if(mark[f(b1,b2)] == 1){
cout << sp << "\n";
exit(0) ;
}
for(int v : nw){
int vi = g(v).F , vj = g(v).S ;
rep(j , 0 , min(vi-1,n-1)){
if(j != 0 && mark[f(vi-j , vj)]==1)break ;
vec[vi-j].pb(vj) ;
ro.pb(vi-j);
}
if(vi-n >= 1){
vec2[vi-n].pb(vj) ;
ro.pb(vi-n) ;
}
rep(j , 1 , min(r-vi , n-1)){
if(j!=0 && mark[f(vi+j , vj)] == 1)break ;
vec[vi+j].pb(vj) ;
ro.pb(vi+j) ;
}
if(vi+n <= r){
vec2[vi+n].pb(vj) ;
ro.pb(vi+n) ;
}
}
vector <int> rr ;
for(int x : ro){
if(ok[x] == 0){
rr.pb(x);
ok[x] = 1;
}
}
sort(all(rr));
for(int x : rr)ok[x] =0 ;
for(int x : rr){
sort(all(vec[x])) ;
sort(all(vec2[x])) ;
rep(i , 0 ,sz(vec[x])-1){
int nx;
if(i == sz(vec[x])-1)nx = c+1 ;
else nx = vec[x][i+1] ;
int z = vec[x][i] ;
rep(j , z , z+n){
if(j >= nx)break ;
if(j != z && mark[f(x , j)] == 1)break ;
if(mark[f(x,j)] == 0){
nw2.pb(f(x,j)) ;
// cout << x<<" " << j << z << "<1--\n";
}
}
}
rep(i , 0 ,sz(vec[x])-1){
int ls;
if(i == 0)ls = 0 ;
else ls = vec[x][i-1] ;
int z = vec[x][i] ;
per(j , z , z-n){
if(j <= ls)break ;
if(j != z && mark[f(x , j)] == 1)break ;
if(mark[f(x,j)] == 0){
nw2.pb(f(x,j)) ;
// cout << x<<" " << j << "<1--\n";
}
}
}
rep(i , 0 ,sz(vec2[x])-1){
int nx;
if(i == sz(vec2[x])-1)nx = c+1 ;
else nx = vec2[x][i+1] ;
int z = vec2[x][i] ;
rep(j , z , z+n-1){
if(j >= nx)break ;
if(j != z && mark[f(x , j)] == 1)break ;
if(mark[f(x,j)] == 0){
nw2.pb(f(x,j)) ;
// cout << x<<" " << j << "<1--\n";
}
}
}
rep(i , 0 ,sz(vec2[x])-1){
int ls;
if(i == 0)ls = 0 ;
else ls = vec2[x][i-1] ;
int z = vec2[x][i] ;
per(j , z , z-n+1){
if(j <= ls)break ;
if(j != z && mark[f(x , j)] == 1)break ;
if(mark[f(x,j)] == 0){
nw2.pb(f(x,j)) ;
// cout << x<<" " << j << "<1--\n";
}
}
}
}
nw.clear() ;
for(int x : nw2){
if(mark[x] == 0){
mark[x] =1 ;
nw.pb(x);
}
}
for(int x : rr){
vec[x].clear() ;
vec2[x].clear() ;
}
}
}
/*
*/
