def kangaroo(x1, v1, x2, v2):
    k1=x1
    k2=x2
    if (x1>x2 and v1>=v2) or (x1<x2 and v1<=v2):
        return'NO'
    if x2>x1:
        while True:
            k1+=v1
            k2+=v2
            if k1==k2:
                return 'YES'
            if k2<k1:
                break
    else:
        while True:
            k1+=v1
            k2+=v2
            if k1==k2:
                return 'YES'
            if k1<k2:
                break
return 'NO'