#include <iostream>
using namespace std;
int main(){
int a, b;
int ld = 0, cd = 0, lk = 0, k = 0, mp = 1, add = 0;
long long sum = 0;
cin >> a >> b;
int* tab = new int[a];
int* wyn = new int[b];
for (int i = 0; i < a; i++)
{
cin >> tab[i];
}
for (int i = 0; i < b; i++)
{
cin >> cd;
cin >> k;
mp = cd - ld;
for (int j = 0; j < a; j++)
{
add = (tab[j] * mp)+lk;
if (add > k){
sum += add-k;
}
}
//cout << endl << sum ;
wyn[i] = sum;
sum = 0;
ld = cd;
lk = k;
}
for (int i = 0; i < b; i++)
{
cout << wyn[i] << endl;
}
cin >> a;
return 0;
}