def calc(x,y):    # count y-bit on [0,x]
    return (x+1)//(1<<(y+1))*(1<<y)+max(0,(x+1)%(1<<(y+1))-(1<<y))
def query(l,r,y): # count y-bit on [l,r]
    return calc(r,y)-calc(l-1,y)
a,b,c,d=map(int,input().split())
answer=0
for i in range(0,32):
    cnt1_ab,cnt1_cd=[query(a,b,i),query(c,d,i)]
    cnt0_ab,cnt0_cd=[b-a+1-cnt1_ab,d-c+1-cnt1_cd]
    xor_ans=cnt1_ab*cnt0_cd+cnt0_ab*cnt1_cd
    answer+=xor_ans*(1<<i)
print(answer)