#include <iostream>
using namespace std;
int main()
{
	int n,m;
	cin >> n >> m;
	int a[n + 1],s[n + 1],l,r;
	cin >> a[1];
	s[0] = 0;
	s[1] = a[1];
	for (int i = 2;i <= n;i++)
	{
		cin >> a[i];
		s[i] = s[i - 1] + a[i];
	}
	for (int j = 1;j <= m;j++)
	{
		cin >> l >> r;
		cout << s[r] - s[l - 1] << endl;
	}
	return 0;
 }