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#include<cstdio>


using namespace std;


typedef long long LL;


#define REP(i,a,b) for(int i=a; i<=b; ++i)


const int MAX_N = 5e5;


LL wys[MAX_N], d, b, last_d = 0, wyn = 0;

int a[MAX_N], n, m;


LL min(LL a, LL b)
{
	return (a<b) ? a : b ;
}


LL max(LL a, LL b)
{
	return (a>b) ? a : b ;
}


int main()
{
	scanf( "%d %d", &n, &m );
	
	REP(i,0,n-1)
	{
		scanf( "%d", &a[i] );
	}
	
	while( m )
	{
		scanf( "%lld %lld", &d, &b );
		
		REP(i,0,n-1)
		{
			wys[i] += ( d - last_d ) * a[i];
		}
		
		REP(i,0,n-1)
		{
			wyn += max( 0, wys[i] - b );
			
			wys[i] = min( b, wys[i] );
		}
		
		printf( "%lld\n", wyn );
		
		wyn = 0;
		
		last_d = d;
		
		--m;
	}
	
	return 0;
}