平行四边形

a=[]
for i in range(0,4):
   m=int(raw_input("please input four numbers"))
   a.append(m)
a.sort()
if a[0]+a[1]+a[2]>=a[3]:
    if a[0]==a[1] and a[2]==a[3]:
        print ("yes")

    else:
     print("no")

else:
    print('error')

print a