#include<cstdio>
#include<cstdlib>
#include<cstring> 
#include<algorithm>
using namespace std;
int a[100010],b[100010],k[1010],p[1010],n,m,now;
long long ans,f[11][1010],*q;
long long min(long long a,long long b)
{
    return a==-1 ? b : (a<b ? a : b); 
}
int main()
{
    while (scanf("%d%d",&n,&m)!=EOF)
    {
        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]);
        ans = 0ll;
        memset(f,-1,sizeof(f));
        for (int i = 1;i<=10;++i) f[i][0] = 0;
        for (int i = 0;i<=10;++i)
        {
            q = f[i];
             for (int j = 1;j <= m;++j)
            {
                if (p[j] <= i) continue;
                now = p[j] - i;
                for (int val = 1;val <= 1000;++val)
                {
                    if (val <= now) q[val] = min(q[val],k[j]);
                    else if (q[val - now]!=-1) q[val] = min(q[val],q[val - now] + k[j]); 
                }
            } 
        }
        for (int i = 1;i<=n;++i)
        {
            if (ans == -1) continue;
            if (f[b[i]][a[i]]==-1) ans = -1;else ans+=f[b[i]][a[i]]; 
        }
        printf("%I64d\n",ans); 
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}