#include<cstdio>
#include<cstring>
#include<algorithm>
#define LL long long
using namespace std;
const LL INF=1e18+7;
LL n,m,f[155][5507];
LL maxp,max1,max2,ans,mn;
LL a[100007],b[100007],v[100007],p[100007];
void first(){
    for(int i=0;i<=max2;i++)
     for(int j=1;j<=max1+maxp;j++)
      f[i][j]=INF;
    for(int k=0;k<=max2;k++)
        for(int i=1;i<=m;i++){
            LL now=p[i]-(LL)k;
            if(now<=0) continue;
            for(int j=1;j<=maxp+max1;j++){
                if(j-now>=0) f[k][j]=min(f[k][j],f[k][j-now]+v[i]);
                else f[k][j]=min(f[k][j],v[i]);
            }
        }
}
int main()
{
    while(scanf("%lld %lld",&n,&m)!=EOF)
    {
        maxp=max1=max2=ans=mn=0;
        for(int i=1;i<=n;i++)
        {
            scanf("%lld%lld",&a[i],&b[i]),
            max1=max(a[i],max1),max2=max(max2,b[i]);
        }
        for(int i=1;i<=m;i++)
        {
            scanf("%lld%lld",&v[i],&p[i]);
            maxp=max(maxp,p[i]);
        }
        if(max2>=maxp)
        {
            printf("-1\n");
            continue;
        }
        
        first();
        for(int i=1;i<=n;i++)            
            ans+=f[b[i]][a[i]];
        
        printf("%lld\n",ans);
    }
    return 0;
}