题解 | 操作数组

import sys

# for line in sys.stdin:
#     a = line.split()
#     print(int(a[0]) + int(a[1]))

def solve():
    input = sys.stdin.readline
    n = int(input())
    a = list(map(int, input().split()))
    b = list(map(int, input().split()))
    sm = 0
    res = 0
    for i in range(n):
        sm += (a[i] - b[i])
        res += abs(a[i] - b[i])

    return res // 2 if sm == 0 else -1 


res = solve()
print(res)