Wannaflt15-A

#include <bits/stdc++.h>
using namespace std;
#define manx 100005
#define ll long long 
priority_queue<int> h;
ll ans=0;
struct node
{
	int capacity,price;
	bool operator<(const node& y)const{
		return capacity<y.capacity;
	}	
};
node Car[manx];
int student[manx],n,m;
int main(){
	ios::sync_with_stdio(false);
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)
		scanf("%d",&student[i]);
	for(int i=1;i<=m;i++)
		scanf("%d%d",&Car[i].capacity,&Car[i].price);
	sort(student+1,student+n+1);
	sort(Car+1,Car+1+m);
	int i,j;
	for(i=n,j=m;i;i--){
		for(;Car[j].capacity>=student[i];j--)
			h.push(-Car[j].price);
		if(h.empty()){
			puts("-1");
			return 0;
		}
		ans-=h.top();
		h.pop();
	}
	cout<<ans<<endl;
	return 0;
}