#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
long long n,m,a[100005],b[100005],v[100005],p[100005],f[12][100005];
long long ans;
int main(){
    while (~scanf("%I64d%I64d",&n,&m)){
        for (int i=1;i<=n;i++) scanf("%I64d%I64d",&a[i],&b[i]);
        for (int i=1;i<=m;i++) scanf("%I64d%I64d",&v[i],&p[i]);
        for (int i=0;i<=10;i++){
                for (int j=1;j<=1000;j++){
                    f[i][j]=10000000000000ll;
                    for (int k=1;k<=m;k++)
                        if (j-max(0ll,p[k]-i)>0) f[i][j]=min(f[i][j],f[i][j-max(0ll,p[k]-i)]+v[k]);
                        else f[i][j]=min(f[i][j],v[k]);
                }
        }
        ans=0;
        for (int i=1;i<=n;i++){
            if (f[b[i]][a[i]]==10000000000000ll){ans=-1;break;}
            ans+=f[b[i]][a[i]];
        }
        printf("%I64d\n",ans);
    }
}