N = int(input())
A = list(map(int, input().split()))
Q = int(input())
query = [list(map(int, input().split())) for _ in range(Q)]

B = [-1]*N
cnt = -1
for i in range(N):
    if A[i] != 0 and (i == 0 or A[i-1] == 0):
        cnt += 1
    if A[i] != 0:
        B[i] = cnt
S = []
SUM = 0
for i in range(N):
    SUM += A[i]
    if 1 <= SUM and A[i] == 0:
        S.append(SUM)
        SUM = 0
if 1 <= SUM:
    S.append(SUM)

for x, b in query:
    x -= 1
    if A[x] == 0:
        SUM = b
        if 1 <= x and A[x-1] != 0:
            SUM += S[B[x-1]]
        if x+1 < N and A[x+1] != 0:
            SUM += S[B[x+1]]
        print(SUM)
    else:
        print(S[B[x]]-A[x]+b)