#include <iostream>
using namespace std;
const int N = 100010;
int a[N];//保存原数组
int s[N];//保存前缀和
int main(){
    int n, m;
    cin >> n >> m;
    //从a[1]开始保存。a[0]是0
    for(int i = 1; i <= n; ++i){
        cin >> a[i];
    }

    s[0] = 0;
    //计算前缀和
    for(int i = 1; i <= n; ++i)
        s[i] = s[i - 1] + a[i];

    for(int i = 0; i < m; ++i){
        int l, r;//保存区间
        cin >> l >> r;
        //s[r] = a[1]+ ··· + a[r]
        //s[l - 1] = a[1]+ ··· + a[l - 1]
        //s[r] - s[l - 1] = a[l] + ··· + a[r]
        cout << s[r] - s[l - 1] << endl;
    }
}