#include <iostream>
#include <cstring>
#include <cstdio>
#include <string>
#include <cmath>
#include <algorithm>
 
using namespace std;
 
void solve (int , int [], int [], int [][1010]);
 
int main ()
{
    int n, m, i;
    int dp[20][1010];
    int a[100010], b[100010];
    int k[1010], p[1010];
    
    while (~scanf ("%d%d", &n, &m))
    {
        for (i = 1; i <= n; i++)
        {
            scanf ("%d%d", &a[i], &b[i]);
        }
        for (i = 1; i <= m; i++)
        {
            scanf ("%d%d", &k[i], &p[i]);
        }
        
        memset (dp, -1, sizeof(dp));
        solve (m, k, p, dp);
        
        long long sum = 0;
        for (i = 0; i <= n; i++)
        {
            if (dp[b[i]][a[i]] == -1)
            {
                sum = -1;
                break;
            }
            sum += dp[b[i]][a[i]];
        }
        printf ("%lld\n", sum);
    }
    
    return 0;
}
 
void solve (int m, int k[], int p[], int dp[][1010])
{
    int i, j, s, harm;
    
    for (i = 0; i <= 10; i++)
    {
        dp[i][0] = 0;
    }
    for (i = 0; i <= 10; i++)
    {
        for (j = 1; j <= 1000; j++)
        {
            for (s = 1; s <= m; s++)
            {
                harm = p[s] - i;
                if (harm <= 0)
                {
                    continue;
                }
                if (harm >= j)
                {
                    if (k[s] < dp[i][j] || dp[i][j] == -1)
                    {
                        dp[i][j] = k[s];
                    }
                }
                else
                {
                    if (k[s] + dp[i][j - harm] < dp[i][j] || dp[i][j] == -1)
                    {
                        dp[i][j] = k[s] + dp[i][j - harm];
                    }
                }
            }
        }
    }
}