python练习 list取重复

import random
def getrandata(num):
a=[]
i=0
while i<num:
a.append(random.randint(0,50))
i+=1
return a
def cross(x,y):
x=list(set(x))
y=list(set(y))
i=0
j=0
c=[]
l1=len(x)
l2=len(y)
for i in range(l1):
for j in range(l2):
if x[i] == y[j]:
c.append(y[j])

return c
if __name__ == "__main__":
x=input("input the first  listlength ")
y=input("input the second listlength ")
x=getrandata(x)
y=getrandata(y)
print x,"\n",y
print cross(x,y)