if __name__ == "__main__":
n, m = map(int, input().split())
nums = list(map(int, input().split()))
prefix = [0] * (n + 10)
for i in range(n):
prefix[i+1] = prefix[i] + nums[i] # 求前缀和
for i in range(m):
l, r = map(int, input().split())
print(prefix[r] - prefix[l-1]) # 求部分和