#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

void Read(long long &p)
{
    p=0;
    char c=getchar();
    while(c<'0'||c>'9') 
        c=getchar();
    while(c>='0'&&c<='9')
        p=p*10+c-'0',c=getchar();
}

const int MAXN=202017;
const int MAXM=2027;

long long n,m,hp[MAXN],pro[MAXN],mp[MAXM],atk[MAXM];
long long dp[12][MAXM],mxatk=-1,mxpro=-1,mxhp=-1;
int main()
{
    while(cin>>n>>m)
    {
        mxpro=-1,mxatk=-1,mxhp=-1;
        for(int i=1;i<=n;i++)
            Read(hp[i]),Read(pro[i]),
            mxpro=max(mxpro,pro[i]),
            mxhp=max(mxhp,hp[i]);
        for(int i=1;i<=m;i++)
            Read(mp[i]),Read(atk[i]),
            mxatk=max(mxatk,atk[i]);

        if(mxatk<=mxpro)
        {
            puts("-1");
            continue;
        }

        memset(dp,0,sizeof dp);
        for(int i=0;i<=mxpro;i++)
            for(int j=1;j<=mxhp;j++)
            {
                dp[i][j]=0x7ffffff7;
                for(int k=1;k<=m;k++)
                {
                    int sub=atk[k]-i;
                    if(sub>=j) dp[i][j]=min(dp[i][j],mp[k]);
                    else if(sub>0) dp[i][j]=min(dp[i][j],dp[i][j-sub]+mp[k]);
                }
            }
        long long ans=0;
        for(int i=1;i<=n;i++)
            ans+=dp[pro[i]][hp[i]];
        cout<<ans<<endl;
    }
}