#include <iostream>

using namespace std;

int main()
{   //這題難在會超時，所以必須找到比較快的方芳
    int n, m;
    while(cin >> n >> m)
    {
        int food[n], sum[n], range[m][2], energy[m];

        for(int i = 0; i < n; i++) //enter energy of food
            cin >> food[i];

        for(int i = 0; i < n; i++) //計算 a1 ~ a"i" 的總和
        {
            sum[i] = 0;
            for(int j = 0; j <= i; j++)
                sum[i] += food[j];
        }

        for(int i = 0; i < m; i++) //enter range(start->[0] & end->[1])
            cin >> range[i][0] >> range[i][1];

        for(int i = 0; i < m; i++) //將 範圍的數字 對應 它在陣列的數字(e.g. 2->1, 5->4)
        {
            range[i][0] -= 1; range[i][1] -= 1;
        }

        for(int i = 0; i < m; i++)//原理 if->[a1~5 = a5]  else->[a2~5 = a5 - a1]
        {
            if(range[i][0]-1 < 0)
                energy[i] = sum[ range[i][1] ];

            else
                energy[i] = sum[ range[i][1] ] - sum[ range[i][0]-1 ];
        }



        for(int i = 0; i < m; i++)
            cout << energy[i] <<endl;
    }
}