#include <stdio.h>
#include <stdlib.h>
#define maxa 1000
//#define maxa 15
#define maxb 10
#define maxn 100000
#define maxm 1000
#define maxf 100000001
//maxp(100000)*maxa(1000)

//maxa*maxb*maxm*case

long f[maxb+1][maxa+1];
long a[maxn+1],b[maxn+1];
long p[maxm+1],q[maxm+1],r[maxm+1];

long max(long a,long b)
{
    if (a>b)
        return a;
    else
        return b;
}

long min(long a,long b)
{
    if (a>b)
        return b;
    else
        return a;
}

int main()
{
    long n,m,i,j,k;
    long bb,qq;
    __int64 ans;
    while (scanf("%ld%ld",&n,&m)!=EOF)
    {
        bb=0;
        qq=0;
        for (i=1;i<=n;i++)
        {
            scanf("%ld%ld",&a[i],&b[i]);
            bb=max(bb,b[i]);
        }
        for (i=1;i<=m;i++)
        {
            scanf("%ld%ld",&p[i],&q[i]);
            qq=max(qq,q[i]);
        }
        if (bb>=qq)
        {
            printf("-1\n");
            continue;
        }
        for (i=0;i<=bb;i++)
        {
            f[i][0]=0;
            for (j=1;j<=maxa;j++)
                f[i][j]=maxf;
            for (k=1;k<=m;k++)
                r[k]=q[k]-i;
            for (j=1;j<=maxa;j++)
                for (k=1;k<=m;k++)
                    if (r[k]>0)
                    {
                         if (j-r[k]<0)
                            f[i][j]=min(f[i][j],p[k]);
                         else
                            f[i][j]=min(f[i][j],f[i][j-r[k]]+p[k]);
                    }
        }
        ans=0;
        for (i=1;i<=n;i++)
            ans=ans+f[b[i]][a[i]];
        printf("%I64d\n",ans);
    }
    return 0;
}
/*
1 2
4 5
7 10
6 8
7
*/
/*
1 2
6 5
7 10
6 8
12
*/