m=[]
m2=[]

for tik in range(3):
    n=int(input())
    m1=input().split()
    for i in m1:
        if i not in m:
            m.append(i)
        elif i in m:
            if i not in m2:
                m2.append(i)

print(len(m)-len(m2))


I don't know why this program doesn't work.

Edited by author 03.05.2021 00:22