#include <iostream>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;
#define mmst(a, b) memset(a, b, sizeof(a))
#define mmcp(a, b) memcpy(a, b, sizeof(b))

typedef long long LL;

const int N=100100;
const LL oo=1e18;
int n,m;
int a[N],b[N];
int p[N];
LL k[N],f[1010][11],ans;

int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
    ans=0;
    for(int i=1;i<=n;i++)
    scanf("%d%d",&a[i],&b[i]);
    
    for(int i=1;i<=m;i++)
    scanf("%I64d%d",&k[i],&p[i]);

    for(int j=0;j<=10;j++)
    for(int i=1;i<=1000;i++)
    {
        f[i][j]=oo;
        for(int l=1;l<=m;l++)
        if(p[l]>j)
        {
            if(i-(p[l]-j)<=0)
            f[i][j]=min(f[i][j],k[l]);
            else
            f[i][j]=min(f[i][j],f[i-(p[l]-j)][j]+k[l]);
        }
    }
    
    for(int i=1;i<=n;i++)
    if(f[a[i]][b[i]]==oo)
    {
        ans=-1;
        break;
    }
    else
    ans=ans+f[a[i]][b[i]];
    
    cout<<ans<<endl;
    }

    return 0;
}