#include<stdio.h>

#define ABS(a) ((a)>0?(a):-(a))

void dfs(int x,int y,int *board,int h,int w,int *flag){
  if(flag[x*w+y]) return;
  flag[x*w+y]=1;

  int d[]={1,0,-1,0,1};
  int i;
  for(i=0;i<4;i++){
    int nx=x+d[i];
    int ny=y+d[i+1];
    if(!(nx>=0 && nx<h && ny>=0 && ny<w)) continue;
    if(ABS(board[x*w+y]-board[nx*w+ny])<=1) dfs(nx,ny,board,h,w,flag);

    int nnx=x+2*d[i];
    int nny=y+2*d[i+1];
    if(!(nnx>=0 && nnx<h && nny>=0 && nny<w)) continue;
    if(board[nnx*w+nny]==board[x*w+y]&&board[nx*w+ny]<board[x*w+y]) dfs(nnx,nny,board,h,w,flag);
  }
  return;
}

void run(void){
  int h,w;
  scanf("%d%d",&h,&w);
  int sx,sy,gx,gy;
  scanf("%d%d%d%d",&sx,&sy,&gx,&gy);
  int board[2500];
  int flag[2500];
  int i,j;
  for(i=0;i<h;i++){
    for(j=0;j<w;j++){
      scanf("%1d",board+i*w+j);
      flag[i*w+j]=0;
    }
  }
  dfs(sx-1,sy-1,board,h,w,flag);
  printf("%s\n",flag[(gx-1)*w+gy-1]?"YES":"NO");
  return;
}

int main(void){
  run();
  return 0;
}