#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;
const int maxn = 2e5 + 10;
int n;
int a[maxn];
ll segment_tree[3 * maxn];

ll merge_nodes(ll A, ll B) {
    return A + B;
}

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


ll query(int i, int j, int L = 0, int R = n - 1, int node = 1) {
    if(R < i or j < L) {
        return 0;
    }
    if(i <= L and R <= j) {
        return segment_tree[node];
    }

    int middle = (L + R) / 2;
    return merge_nodes(query(i, j, L, middle, 2 * node), query(i, j, middle + 1, R, 2 * node + 1));
}

int main() {
    int k;
    cin >> n >> k;

    for(int i = 0; i < n; i++) {
        cin >> a[i];
    }

    build_tree(0, n - 1, 1);

    for(int i = 0; i < k; i++) {
        int x, y;
        cin >> x >> y;

        cout << query(x - 1, y - 1) << endl;
    }

    return 0;
}