#include <cstdio>
#include <climits>
#include <iostream>
#include <algorithm>
using namespace std;

typedef long long ll;

const int maxw = 1e3 + 5 , maxb = 10 + 5;

int n , m;
ll s[maxb][maxw] , f[maxb][maxw];

int main()
{
    while (~scanf("%d %d" , &n , &m))
    {
        for (int i = 0; i <= 10; i++)
        {
            f[i][0] = s[i][0] = 0;
            for (int j = 1; j <= 1000; j++)
                f[i][j] = INT_MAX , s[i][j] = 0;
        }
        int mb = 0 , ma = 0;
        for (int i = 1; i <= n; i++)
        {
            int a , b;
            scanf("%d %d" , &a , &b);
            ma = max(ma , a);
            mb = max(mb , b);
            s[b][a]++;
        }
        for (int k = 1; k <= m; k++)
        {
            int w , v;
            scanf("%d %d" , &v , &w);
            for (int i = 0; i <= mb; i++)
                if (w > i)
                    for (int j = 1; j <= ma; j++)
                    {
                        int from = j + i - w;
                        if (from < 0)
                            from = 0;
                        f[i][j] = min(f[i][j] , f[i][from] + v);
                    }
        }
        ll ans = 0; bool flag = false;
        for (int i = 0; i <= mb; i++)
            for (int j = 0; j <= ma; j++)
            if (s[i][j])
            {
                if (f[i][j] == INT_MAX)
                {
                    ans = -1;
                    goto num;
                }
                ans += s[i][j] * f[i][j];
            }
        num:cout << ans << endl;
    }
    return 0;
}