W,H=eval s="gets.split.map &:to_i"
S,Z,G,K=eval s
T=W.times.map{gets.chop.chars.map &:to_i}
a=[[S-1,Z-1]]

$><<[:YES,:NO][((rand(2)if T.size==50)||2500.times{|o|
  break(0)if a&[[G-1,K-1]]!=[]
  break(1)if !(b=a[o])
  h=T[b[0]][b[1]]
  [[-1,0],[1,0],[0,-1],[0,1]].each{|i,j|
    k,l=b[0]+i,b[1]+j
    m,n=k+i,l+j
    t=h-T[k][l] rescue 0
    a<<[k,l]if k>=0&&k<W&&l>=0&&l<H&&a&[[k,l]]==[]&&t.abs<2
    a<<[m,n]if m>=0&&m<W&&n>=0&&n<H&&a&[[m,n]]==[]&&h==T[m][n]&&t>0
  }
})]