1501A - Alexey and Train - CodeForces Solution

t = int(input())
ans = []
for i in range(t):
    a = [0]
    b = [0]
    n = int(input())
    for j in range(n):
        ai, bi = map(int, input().split())
        a.append(ai)
        b.append(bi)
    time = 0
    tm = [0]
    tm += [int(x) for x in input().split()]
    diff = 0
    for k in range(1, n + 1):
        time += a[k] - b[k - 1] + tm[k]
        if k != n:
            time += (b[k] - a[k] + 1) // 2
            if time < b[k]:
                time += b[k] - time
        else:
            continue
    ans.append(time)
for _ in range(len(ans)):
    print(ans[_])