import java.util.Scanner;
public class Main{
static int depth=0;
static int parr[][]=null,stack[][]=null;
static int n,m,enr,enc,maxstep=0,step=0;
public static void main
(String args
[]) {
int str,stc;
Scanner scan
=new Scanner
(System.
in); n=scan.nextInt();
m=scan.nextInt();
str=scan.nextInt()-1;
stc=scan.nextInt()-1;
enr=scan.nextInt()-1;
enc=scan.nextInt()-1;
parr=new int [n][m];
parr[str][stc]=1;
stack=new int [n*m+1][8];
//
// find(str,stc,1);
stack[0][0]=str;stack[0][1]=stc;stack[0][2]=step;stack[0][3]=0;
//stack[0][0]=str;stack[0][1]=stc;stack[0][2]=step;
int i,nstr,nstc;
while(stack[0][3]<=4)
{
//System.out.println(step);
i=++stack[step][3];
//str=stack[step]
if(i>4){parr[stack[step][0]][stack[step][1]]=0; /* stack[step][3]=0;*/ step--;continue;}
str=stack[step][0];
stc=stack[step][1];
nstr=str;
nstc=stc;
if(i==1)
{
if(str>0 && parr[str-1][stc]!=1)
nstr-=1;
}
if(i==2)
{
if(stc>0 && parr[str][stc-1]!=1)
nstc-=1;
}
if(i==3)
{
if(str<n-1 && parr[str+1][stc]!=1)
nstr+=1;
}
if(i==4)
{
if(stc<n-1 && parr[str][stc+1]!=1)
nstc+=1;
}
if(str==nstr && stc==nstc)
{
continue;
}
else
{
//parr[nstr][nstc]=1;
//step++;
//chk target reached
if(nstr==enr && nstc==enc)
{
if(maxstep==0)maxstep=step+1;else if(step+1>maxstep){maxstep=step+1;/*System.out.println(step+1);*/}
//step--;
//parr[nstr][nstc]=0;
continue;
}
else
{
parr[nstr][nstc]=1;
step++;
//find(nstr,nstc,step);
stack[step][0]=nstr;stack[step][1]=nstc;stack[step][3]=0;
//step--;
// depth--;
// System.out.println(depth);
//parr[nstr][nstc]=0;
}
}
}
System.
out.
println("Maximum step="+(maxstep
+1));
}
}
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