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

int main()
{
    int n, m, i;
    long long D[11][1101];
    while (cin>>n>>m)
    {
        int flag[11] = {};//def vector blood
        int minus = 0;//max of attack
        int *blo = new int[n];
        int *def = new int[n];
        for (i=0; i<n; i++)
        {
            cin>>blo[i]>>def[i];
            flag[def[i]] = max(blo[i], flag[def[i]]);
        }

        int *sto = new int[m];
        int *att = new int[m];
        for (i=0; i<m; i++)
        {
            cin>>sto[i]>>att[i];
            minus = max(att[i], minus);
        }

        for (i=0; i<=10; i++)//def
        {
            if (flag[i])
            {
                if (minus<=i)
                {
                    for (int j=1; j<=flag[i]; j++)//blood
                    {
                        D[i][j] = -1;
                    }
                }
                else
                {
                    D[i][0] = 0;
                    for (int j=1; j<=flag[i]; j++)//blood
                    {
                        D[i][j] = 1e17;
                        for (int k=0; k<m; k++)
                        {
                            D[i][j] = min(D[i][max(0, j-max(0, att[k]-i))]+sto[k], D[i][j]);
                        }
                    }
                }
            }
        }
        long long sum = 0;
        for (i=0; i<n; i++)
        {
            if (D[def[i]][blo[i]]==-1)
            {
                sum = -1;
                break;
            }
            sum += D[def[i]][blo[i]];
        }

        cout<<sum<<endl;
        delete[] blo;
        delete[] def;
        delete[] att;
        delete[] sto;
    }
    return 0;
}