#include <iostream>
using namespace std;
const int maxn = 200005;
typedef long long ll;
ll a[maxn];
int n;

ll segment_tree[3 * maxn];

void build_tree(int L, int R, int position) {
    if(L == R) {
        segment_tree[position] = a[L];
    }
    else {
        int mid = (L + R) / 2;
        build_tree(L, mid, 2 * position);
        build_tree(mid + 1, R, 2 * position + 1);

        segment_tree[position] = segment_tree[2 * position] + segment_tree[2 * position + 1];
    }

}
// L R i L R j L R
ll query(int L, int R, int position, int i, int j) {
    if(R < i or j < L) {
        return 0;
    }
    if(i <= L and R <= j) {
        return segment_tree[position];
    }
    int mid = (L + R) / 2;
    return query(L, mid, 2 * position, i, j) + query(mid + 1, R, 2 * position + 1, i, j);
}
int main()
{
    int q;
    cin >> n >> q;
    for(int i = 0; i < n; i++) {
        cin >> a[i];
    }

    build_tree(0, n - 1, 1);

    for(int i = 0; i < q; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;

        cout << query(0, n - 1, 1, a, b) << endl;
    }
    return 0;
}