#include <stdio.h>  
#include <string.h>    
#include <iostream>    
#include <algorithm>  
using namespace std;
typedef long long ll;
const int INF = 0x3f3f3f3f;

ll a[120000], b[120000];
ll k[1200], p[1200];
ll dp[1200][22];//dp[i][j]生命为i防御为j的怪兽所需水晶  
int main()
{
    int n, m;
    while (cin >> n >> m)
    {
        for (int i = 0; i < n; i++)
            scanf("%d%d", &a[i], &b[i]);

        ll maxp = 0;
        for (int i = 0; i < m; i++)
        {
            scanf("%d%d", &k[i], &p[i]);
            maxp = max(maxp, p[i]);
        }
        int flag = 0;
        for (int i = 0; i < n; i++)
        {
            if (b[i] >= maxp) {
                flag = 1;
                break;
            }
        }
        if (flag) {
            puts("-1");
            continue;
        }
        memset(dp, INF, sizeof(dp));
        for (int j = 0; j <= 12; j++)
            dp[0][j] = 0;
        for (int x = 0; x < m; x++)
        {
            for (int j = 0; j <= 10; j++)
                for (int i = 0; i <= 1000; i++)
                {
                    if (p[x] <= j)continue;
                    if (i <= p[x] - j)//不堪一击or恰好一击   
                        dp[i][j] = min(dp[i][j], k[x]);
                    else if (dp[i][j] > dp[i - (p[x] - j)][j] + k[x])
                        dp[i][j] = dp[i - (p[x] - j)][j] + k[x];
                }
        }
        ll sum = 0;
        for (int i = 0; i < n; i++)
        {
            sum += dp[a[i]][b[i]];
        }
        cout << sum << endl;
    }
    return 0;
}