x=int(input())
y=int(input())
xx=int(input())
yy=int(input())
xsp=x+1
xsm=x-1
ysp=y+1
ysm=y-1

if(xx>=1 and xx<=8 and yy>=1 and yy<=8):
    if(xsp==xx and ysp==yy) or (xsm==xx and ysp==yy) or (xsp==xx and ysm==yy) or (xsm==xx and ysm==yy):
        print("YES")
    elif(xsp==xx and yy==y) or (xsm==xx and yy==y) or (xsp==xx and yy==y) or (xsm==xx and yy==y):
        print("YES")
    elif(xx==x and ysp==yy) or (xx==x and ysm==yy) or (xx==x and ysp==yy) or (xx==x and ysm==yy):
        print("YES")
    else:
        print("NO")
else:
    print("NO")