#include<bits/stdc++.h>
using namespace std;
int a[100005],b[100005];
int F[11][1005],n,m,u,i,oo,ok,k,p,q,v;
long long ans;
int main(){
  while (scanf("%d%d",&n,&m)!=EOF){
    for (i=1;i<=n;i++)
      scanf("%d%d",&a[i],&b[i]);
    memset(F,60,sizeof(F));
    for (u=0;u<=10;u++) F[u][0]=0;
    oo=F[0][1];//printf("%d\n",oo);
    for (i=1;i<=m;i++){
      scanf("%d%d",&k,&p);
      for (u=0;u<=10;u++)
        if (p>u){
          q=p-u;
          for (v=0;v<=1000;v++)
            F[u][min(1000,v+q)]=min(F[u][min(1000,v+q)],F[u][v]+k);
          for (v=999;v>=0;v--)
            F[u][v]=min(F[u][v],F[u][v+1]);
        }
    }
    ans=0;ok=1;
    for (i=1;i<=n&&ok;i++)
      if (F[b[i]][a[i]]==oo) ok=0;else ans+=F[b[i]][a[i]];
    if (!ok) puts("-1");else cout<<ans<<endl;
  }
}