#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<cstring>
#include<map>
#include<set>
#include<queue>
#include<vector>
#include<algorithm>
#include<string>
#define ll long long
#define eps 1e-10
#define LL unsigned long long
using namespace std;
const int INF=0x3f3f3f3f;
const int N=100000+100;
const int mod=998244353;
int a[N],b[N];
struct node{
    int k,p;
}val[N];
ll dp[1010][20];
ll minn[N];
bool cmp(node a,node b)
{
    return a.k-a.p<b.k-b.p;
}
int main()
{
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        int maxx1=0;
        int maxx2=0;
        memset(minn,INF,sizeof(minn));
        for(int i=0;i<n;i++){
          scanf("%d%d",&a[i],&b[i]);
          maxx1=max(maxx1,b[i]);
        }
        for(int i=0;i<m;i++){
          scanf("%d%d",&val[i].k,&val[i].p);
          maxx2=max(maxx2,val[i].p);
        }
        for(int i=0;i<1010;i++)
        for(int j=0;j<20;j++)dp[i][j]=1e10;
        for(int j=0;j<=10;j++)dp[0][j]=0;
        sort(val,val+m,cmp);
        for(int k=0;k<=10;k++)
        for(int i=0;i<m;i++)
        for(int j=1;j<=1000;j++){
            if(j-val[i].p+k<=0)dp[j][k]=min((ll)val[i].k,dp[j][k]);
           else
            dp[j][k]=min(dp[j][k],dp[j-val[i].p+k][k]+val[i].k);

        }
        ll ans=0;
        for(int i=0;i<n;i++){
            ans=ans+dp[a[i]][b[i]];
        }
        if(maxx2<=maxx1)cout<<-1<<endl;
        else
            printf("%I64d\n",ans);
    }
    return 0;
}