#include <bits/stdc++.h>
#define maxs 2020202
#define inf 0xfffffffffffff
#define mme(i,j) memset(i,j,sizeof(i))
using namespace std;

int hp[100005];
int de[100005];
int mp[10005];
int injure[10005];


long long dp[10005][15];
int cost[1005];


//int cmpmon(node a,node b)
//{
//    return a.de<=b.de;
//}
//
//int cmpkill(nnode a,nnode b){
//    return a.injure<=b.injure;
//}

int main()
{
    int n,m;
    while(~scanf("%d%d",&n,&m))
    {
        for(int i=0;i<1007;i++) cost[i] = 100000;
       for(int i=0;i<1011;i++)
       {
           for(int j=0;j<20;j++)
           {
               dp[i][j]=inf;
           }
       }
        int mxde=-1;
        for(int i=1;i<=n;i++){
            scanf("%d%d",&hp[i],&de[i]);
            if(mxde<de[i]) mxde =  de[i];
        }

        int mxin=-1;
        for(int i=1;i<=m;i++)
        {
            scanf("%d%d",&mp[i],&injure[i]);
            if(mxin < injure[i]) mxin=injure[i];
            cost[ injure[i] ] = min( cost[ injure[i] ] ,mp[i] );
        }

        if(n==0)
        {
            puts("0");
            continue;
        }

        if(mxin<=mxde||m==0){ puts("-1"); continue; }

        for(int i=0;i<=1010;i++)
        {
            for(int j=0;j<=11;j++)
            {
                dp[0][j]=0;
               for(int injure=0;injure<=mxin+1;injure++)
               {
                   if( cost[injure] == 100000) continue;
                    int hp  = injure - j;
                    if(hp<=0) continue;

                    if(i-hp>=0)
                    {
                        dp[i][j] = min(dp[i][j],dp[i-hp][j]+cost[injure]);
                    }
                }
            }
        }

        for(int i=1009;i>=0;i--)
        {
            for(int j=0;j<=10;j++)
                dp[i][j]=min(dp[i][j],dp[i+1][j]);
        }


        long long tp;
        int fl=0;
        long long ans=0;
        for(int i=1;i<=n;i++)
        {
            tp = inf;
            for(int j=0;j<=11;j++)
            {
                if(j>=de[i]){
                    tp=min( tp,dp[ hp[i] ][ j ] );
                }
            }
            if(tp == inf ) {
                    ans=-1;
                    break;
            }
            ans+=tp;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}