#include <stdio.h>
#include <string.h>
int main(void)
{
int m,n,i1,j1,k1,l1;
int xs[1024]={0},ys[1024]={0},spread[1024][1024]={0};
int time=0,al=0,ah=2;
int x=0,y=0;
scanf("%d,%d,%d,%d,%d,%d",&m,&n,&i1,&j1,&k1,&l1);
xs[0]=i1;ys[0]=j1;
xs[1]=k1;ys[1]=l1;
spread[i1][j1]=1;
spread[k1][l1]=1;
while(al<ah)
{
int size=ah-al;
for(int j=0;j<size;j++)
{
x=xs[al];
y=ys[al];
al++;
if((x+1)>=0 && (x+1)<m && spread[x+1][y]==0)
{
spread[x+1][y]=1;
ah++;
xs[ah]=x+1;
ys[ah]=y;
}
if((x-1)>=0 && (x-1)<m && spread[x-1][y]==0)
{
spread[x-1][y]=1;
ah++;
xs[ah]=x-1;
ys[ah]=y;
}
if((y+1)>=0 && (y+1)<n && spread[x][y+1]==0)
{
spread[x][y+1]=1;
ah++;
xs[ah]=x;
ys[ah]=y+1;
}
if((y-1)>=0 && (y-1)<n && spread[x][y-1]==0)
{
spread[x][y-1]=1;
ah++;
xs[ah]=x;
ys[ah]=y-1;
}
}
time++;
}
printf("%d",time);
}