#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <map>
using namespace std;

long long n, m;

int monsters[11][1001];
bool has[11];

int costs[1001];
int kills[1001];

long long f[1001];

long long process()
{
    memset(monsters, 0, sizeof(monsters));
    memset(has, 0, sizeof(has));

    for (int i = 0; i < n; ++i)
    {
        int life, def;
        cin >> life >> def;
        monsters[def][life]++;
        has[def] = true;
    }

    int maxKill = 0;
    for (int i = 0; i < m; ++i)
    {
        cin >> costs[i] >> kills[i];
        if (kills[i] > maxKill)
        {
            maxKill = kills[i];
        }
    }

    // cout << maxKill;

    for (int i = maxKill; i < 11; ++i)
    {
        if (has[i]) return -1;
    }

    long long total = 0;

    for (int i = 0; i < 11; ++i)
    {
        memset(f, 0x7f, sizeof(f));

        f[0] = 0;
        for (int j = 1; j <= 1000; ++j)
        for (int k = 0; k < m; ++k)
        {
            if (kills[k] > 0)
            {
                int t = j - kills[k];
                long long c = t >= 0 ? f[t] : 0;
                f[j] = min(f[j], c + costs[k]);
            }
        }

        for (int l = 0; l <= 1000; ++l)
        {
            total += f[l] * monsters[i][l];
        }
        for (int k = 0; k < m; ++k)
        {
            --kills[k];
        }
    }
    return total;
}

int main(void)
{
    while (cin >> n >> m)
    {
        cout << process() << endl;
    }
    return 0;
}