重点是最后一行最后一个指针要-1
N, M = map(int, input().split())
sequence = list(map(int, input().split()))
m_list = []
for i in range(M):
m_list.append(list(map(int, input().split())))
s_sum = [0]
for i in range(N):
s_sum.append(s_sum[-1] + sequence[i])
for i in range(M):
print(s_sum[m_list[i][1]] - s_sum[m_list[i][0] - 1])