#include <bits/stdc++.h>
using namespace std;
int n, m, a[100005], b[100005], k[1005], p[1005];
long long f[15][2005], ans;
int main()
{
    while (~scanf("%d%d", &n, &m))
    {
        for (int i = 1; i <= n; i++) scanf("%d%d", a + i, b + i);
        for (int i = 1; i <= m; i++) scanf("%d%d", k + i, p + i);
        memset(f, 0x7f7f7f, sizeof f);
        for (int i = 0; i <= 10; i++)
        {
            f[i][0] = 0;
            for (int j = 0; j <= 1000; j++)
                for (int l = 1; l <= m; l++)
                    if (p[l] > i)
                        f[i][j + p[l] - i] = min(f[i][j + p[l] - i], f[i][j] + k[l]);
            for (int j = 2000; j >= 0; j--) f[i][j] = min(f[i][j], f[i][j + 1]);
        }
        ans = 0;
        for (int i = 1; i <= n; i++)
            if (f[b[i]][a[i]] == f[11][0])
            {
                ans = -1;
                break;
            }
            else ans += f[b[i]][a[i]];
        cout << ans << endl;
    }
    return 0;
}