#include <iostream>

using namespace std;

long long p[500005],a[500005];
long long n,m,d,b,s,dl=0,dr,r;

int main(){
	ios_base::sync_with_stdio(0);
	cin>>n>>m;
	for(long long i=0;i<n;i++)
		cin>>a[i];
	while(m--){
		cin>>d>>b;
		s=0;
		dr=d-dl;
		for(long long i=0;i<n;i++){
			p[i]+=dr*a[i];
			r=p[i]-b;
			if(r>0){
				s+=r;
				p[i]=b;
			}
		}
		dl=d;
		cout<<s<<endl;
	}
	
	
	return 0;
}