#include<stdio.h>
#include<algorithm>
#include<string.h>
using namespace std;
#define __int64 long long
const int maxm = 1000005;
const __int64 INF = 1e15;
struct node
{
    int h;
    __int64 w;
    bool operator<(const node &r)const
    {
        return w < r.w;
    }
}f[20005];
int a[20005][15] = { 0 }, n, m, p[maxm];
__int64 dp[2005], k[maxm];
void find(int cnt);
int main()
{
    int i, j, sum, x, y, r, flag, cnt;
    __int64 ans, rev, xx;
    while (scanf("%d%d", &n, &m) != EOF)
    {
        memset(a, 0, sizeof(a));
        for (i = 1;i <= n;i++)
        {
            scanf("%d%d", &x, &y);
            a[x][y]++;
        }
        for (i = 1;i <= m;i++)
            scanf("%I64d%d", &k[i], &p[i]);
        flag = 1;ans = 0;
        for (j = 0;j <= 10;j++)
        {
            cnt = 0;
            for (r = 1;r <= m;r++)
            {
                if (p[r] - j <= 0) continue;
                f[++cnt].h = p[r] - j;
                f[cnt].w = k[r];
            }
            find(cnt);
            rev = INF;
            for (i = 1000;i >= 1;i--)
            {
                rev = min(rev, dp[i]);
                if (a[i][j] > 0)
                {
                    if (rev == INF) { flag = 0;break; }
                    ans += (__int64)(rev*a[i][j]);
                }
            }
            if (flag == 0) break;
        }
        if (flag == 0) printf("-1\n");
        else printf("%I64d\n", ans);
    }
    return 0;
}
void find(int cnt)
{
    memset(dp, 1, sizeof(dp));
    for (int i = 1;i <= cnt;i++)
        dp[f[i].h] = min(dp[f[i].h], f[i].w);
    for (int i = 1;i <= 1000;i++)
    {
        for (int j = 1;j <= cnt;j++)
        {
            dp[i + f[j].h] = min(dp[i + f[j].h], dp[i] + f[j].w);
            if (i + f[j].h >= 1000) dp[1000] = min(dp[1000], dp[i + f[j].h]);
        }
    }
}