NZEC error

I am getting NZEC error and exit code 1
please anyone could help me with the error

t = int(input())
a = []
while t > 0:
n = int(input())
for i in range(n):
b = list(map(str,input().split()))
a = a + b

for i in range(0,len(a),2):
    flag = 0

    for j in range(0,len(a),2):
        if i != j:
            if a[i] == a[j]:
                flag = 1

                flag = 0

    if flag == 1:


I suppose this error comes when you try to submit the code without giving the custom input, right?
NZEC error is related to input error.
When you run a program on the codechef IDE which requires a input from the user, you have to provide the custom input with it, which is present beside the run button. If you don’t, there would be no input to give to the program, and thus NZEC error occurs.


I provided custom input and run the code, it run successfully with desired output. But when i m submitting it, again i am getting that NZEC error. Here is the link to my solution.

Thank You, it worked!