#include <bits/stdc++.h>
#define MAXN 100005
#define MAXM 1005
#define ll long long

using namespace std;

int n,m;
int heath[MAXN],defence[MAXN],cost[MAXM],dam[MAXM];
ll dp[MAXM*2],best[2005][15];

int main()
{
    while(cin >> n >> m)
    {
        int max_def = 0, max_hea=0,max_dam=0;
        for(int i=1; i<=n; i++)
        {
            scanf("%d%d",&heath[i],&defence[i]);
            max_def = max(max_def,defence[i]);
            max_hea = max(max_hea,heath[i]);
        }
        for(int i=1; i<=m; i++)
        {
            scanf("%d%d",&cost[i],&dam[i]);
            max_dam = max(max_dam,dam[i]);
        }
        if(max_dam<=max_def)
        {
            printf("-1\n");
            continue;
        }

        memset(best,0x3f,sizeof best);
        for(int def=0; def<=max_def; def++)
        {
            best[0][def] = 0;
            for(int i=1; i<=m; i++)
            {
                if(dam[i]<=def)
                    continue;
                for(int j=dam[i]-def; j<=max_hea+max_dam; j++)
                    best[j][def] = min(best[j][def],best[j-dam[i]+def][def] + cost[i]);
            }
        }
        for(int def=0; def<=max_def; def++)
            for(int j=max_hea+max_dam; j>=1; j--)
                if(best[j][def]<best[j-1][def])
                    best[j-1][def] = best[j][def];
        ll ans = 0;
        for(int i=1; i<=n; i++)
        {
            ans += best[heath[i]][defence[i]];
        }
        printf("%lld\n",ans);
    }
    return 0;
}