from itertools import accumulate
from operator import sub

N = int(input())
M = int(input())
A = list(map(int, input().split()))
L = int(input())
B = list(map(int, input().split()))

S = set(accumulate(A, initial=0))
T = set(accumulate(B, initial=N, func=sub))
U = S | T

print(N + 1 - len(U))