// Longest path on a grid
 
#include<bits/stdc++.h>
 
using namespace std ;
typedef long long ll ;
 
int n, m ;
bool visited[10][10] ;
 
int ff(int x1, int y1, int x2, int y2){
 
	/*if(x1 or x2 is out of bounds or visited before)
		return -INF (inf can be 100 as the grid is low in area)*/
	if(x1 >= n || y1 >= m || x1 < 0 || y1 < 0 || visited[x1][y1])
		return -100 ;
 
	if(x1 == x2 && y1 == y2)
		return 0 ;
 
	visited[x1][y1] = 1 ;
 
	int v1 = 1 + ff(x1 + 1, y1, x2, y2) ;
	int v2 = 1 + ff(x1, y1 + 1, x2, y2) ;
	int v3 = 1 + ff(x1 - 1, y1, x2, y2) ;
	int v4 = 1 + ff(x1, y1 - 1, x2, y2) ;
 
	visited[x1][y1] = 0 ;
 
	return max( max(v1, v2) , max(v3, v4) ) ;
 
}
 
// also print the path? can be multiple paths though
void solve(){
 
    for(int i = 0 ; i < 10 ; i++)
        for(int j = 0 ; j < 10 ; j++)
            visited[i][j] = 0 ;
 
	cin >> n >> m ;
	int x1, y1, x2, y2 ; cin >> x1 >> y1 >> x2 >> y2 ;
 
	string mat[n] ;
	for(int i = 0 ; i < n ; i++) cin >> mat[i] ;
	for(int i = 0 ; i < n ; i++)
        for(int j = 0 ; j < m ; j++)
            if(mat[i][j] == '#')
                visited[i][j] = 1 ;
 
	int ans = ff(x1, y1, x2, y2) ;
 
	if(ans < 0)
        cout << "-1\n" ;
    else
        cout << ans << "\n" ;
 
}
 
int main(){
 
	#ifndef ONLINE_JUDGE
	freopen("sample input.txt", "r", stdin) ;
	freopen("output.txt", "w", stdout) ;
	#endif
 
	ios::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0) ;
 
	int t ; cin >> t ;
	while(t--) solve() ;
 
	return 0 ;
}
 

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