#rabirynce
def ab(a1):
    if a1<0:
        a1*=-1
    return a1
h,w=(int(i) for i in input().split())
sx,sy,gx,gy=(int(i) for i in input().split())
b=[list(input()) for i in range(h)]
for i in range(h):
    for j in range(w):
        b[i][j]=int(b[i][j])
vn=[[sx,sy]]
v=[[0,0]]
Nd=0
i=0
a=[[0]*w]*h
while Nd<1 and vn!=[] and i<h*w+1:
    j=0
    v=vn
    vn=[]
    while j<len(v):
        tx=v[j][0]
        ty=v[j][1]
        k=-1
        while k<2:
            l=-1
            while l<2 and ab(k)+ab(l)<2:
                ux=tx+k
                uy=ty+l
                if ux>=0 and ux<h and uy>=0 and uy<w and a[ux][uy]==0:
                    if b[tx][ty]==b[ux][uy] or ab(b[tx][ty]-b[ux][uy])==1:
                        if ux==gx and uy==gy:
                            Nd=1
                        a[ux][uy]=1
                        vn.append([ux,uy])
          #              print(vn)
                    elif b[tx][ty]>b[ux][uy]:
                        k1=k*2
                        u1x=tx+k1
                        l1=l*2
                        u1y=ty+l1
                        if u1x>=0 and u1x<h and u1y>=0 and u1y<w and a[u1x][u1y]==0:
                            if b[tx][ty]==b[u1x][u1y]:
                                if ux==gx and uy==gy:
                                    Nd=1
                                a[u1x][u1y]=1
                                vn.append([u1x,u1y])
                l+=1
            k+=1
        j+=1
    i+=1
if Nd==1:
    p="YES"
else:
    p="NO"
print(p)