# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
# input = sys.stdin.readline

N = int(input())
M1 = int(input())
A = list(map(int,input().split()))
M2 = int(input())
B = list(map(int,input().split()))

dp = [False]*(N+1)
dp[0]=True
dp[N] = True
now = 0
for a in A:
    now += a
    dp[now] = True
    
now = N
for b in B:
    now -= b
    dp[now] = True
print(N+1-sum(dp))