#include<bits/stdc++.h> 
using namespace std;

int n, m;

class M
{
    public:
        int health, defence;
        M();
        M(int health, int defence);
};

M::M(){}

M::M(int health, int defence)
{
    this->health=health;
    this->defence=defence;
}

class A
{
    public:
        int cost, harm;
        A();
        A(int cost, int harm);
};

A::A(){}

A::A(int cost, int harm)
{
    this->cost=cost;
    this->harm=harm;
}

M ms[100001];
A a[1001];

long long amap[1001][11];

int maxa=0, maxh=0, maxd=0;

long long calc()
{
    // check
    if(maxd>=maxa)return -1;
    
    // init
    for(int i=0;i<=maxd;i++)
        amap[0][i]=0;
        
    long long remain_health, new_cost;
    for(int i=1;i<=maxh;i++)
    {
        for(int j=0;j<=maxd;j++)
        {
            for(int k=0;k!=m;k++)
            {
                if(a[k].harm<=j)continue;    
                remain_health = i-(a[k].harm-j);
                remain_health = max((long long)0, remain_health);
                new_cost = a[k].cost+amap[remain_health][j];
                if(amap[i][j]>=0)amap[i][j]=min(new_cost, amap[i][j]);
                else amap[i][j]=new_cost;
            }
        }
    }
    
    // attack
    long long sum=0;
    for(int i=0;i!=n;i++)
        sum+=amap[ms[i].health][ms[i].defence];
    return sum;
}

int main()
{
    //freopen("in.txt", "r", stdin);
    while(~scanf("%d %d", &n, &m))
    {
        memset(amap, -1, sizeof(amap));
        maxa=0;
        maxh=0;
        maxd=0;
        for(int i=0;i<n;i++)
        {
            scanf("%d %d", &ms[i].health, &ms[i].defence);
            maxh = max(ms[i].health, maxh);
            maxd = max(ms[i].defence, maxd);
        }
        for(int i=0;i<m;i++)
        {
            scanf("%d %d", &a[i].cost, &a[i].harm);
            if(a[i].harm==0)
            {
                m--;i--;
            }
            maxa = max(maxa, a[i].harm);
        }
        long long ans = calc();
        printf("%lld\n", ans);
    }
    return 0;
}