//如題測試都過但是提交卻出現記憶體區段的問題
#include<iostream>
using namespace std;
int main()
{
int n, m, i, x, y,total;
int plus[1001] = { 0 }, sum[1000] = { 0 };
while (cin >> n >> m)
{
for (i = 0; i < n; i++)
{
cin >> plus[i];
sum[i + 1] += plus[i];
sum[i + 1] += sum[i];
}
for (i = 0; i < m; i++)
{
cin >> x >> y;
total = sum[y] - sum[x-1];
cout << total<<endl;
}
}
return 0;
}