#include <iostream>
#include <vector>
using namespace std;

class FoodList{

    public:
        FoodList(int length_){
            length = length_;
        }
        void createAccumulatingList(){
            int tmpValue = 0;
            for (int i = 0; i < length; i++){
                accumulatingList.push_back(list[i] + tmpValue);
                tmpValue = accumulatingList[i];
            }
        }
        vector<int> list;
        vector<int> accumulatingList;
    private:
        int length;
};


int main(){

    int n, m;
    while(cin >> n){
        cin >> m;
        FoodList myFoodList(n);
        // food value
        for (int i = 0; i < n; i++){
            int value;
            cin >> value;
            myFoodList.list.push_back(value);
        }

        // ValueSumUp
        myFoodList.createAccumulatingList();

/*
// debugging
        for (vector<int>::iterator it = myFoodList.accumulatingList.begin();
             it != myFoodList.accumulatingList.end();
             it++ )
        {
            cout << *it << " ";
        }
        cout << endl;
*/
// calculate
        for (int i = 0; i < m; i++){
            int sum = 0;
            int start, end;
            cin >> start >> end;
            if ((start-2) < 0)
                sum =  myFoodList.accumulatingList[end-1];
            else
                sum += myFoodList.accumulatingList[end-1] -  myFoodList.accumulatingList[start-2];
            cout << sum << endl;
        }

    }// end while

}