Help me to fix the error???

Question

a = int(input())
o = []
for i in range(a):
i = int(input())
for j in range(i):
j = input().split()
o = o+j
for k in o:
s = o.count(k)
if s>1:
print(k)

Answer 1

Double use of i and j

Answer 2

Well first you say i in for loop then you try to change it by making it equal to input same for j

just use some other name to define a for loop

Answer 3

👍👍

Answer 4

Explain me plz?