#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
int n,m,mx1,ss,mx2,ok,now,x,i,j,k;
int long long sum;
int a[200005],b[200005],K[200005],p[200005],dp[15][2005];
int main()
{
    while (scanf("%d %d",&n,&m)!=EOF)
    {
        mx1=mx2=ss=0;
        for (i=1;i<=n;i++)
        {
            scanf("%d%d",&a[i],&b[i]);
            mx1=max(mx1,b[i]);
            ss=max(ss,a[i]);
        }
        for (i=1;i<=m;i++)
        {
            scanf("%d%d",&K[i],&p[i]);
            mx2=max(mx1,p[i]);
        }
        //if (mx1>=mx2){puts("-1");continue;}
        for (i=0;i<=mx1;i++)
            for (j=0;j<=ss;j++)
                dp[i][j]=2e9;
        for (i=0;i<=mx1;i++)dp[i][0]=0;
        for (i=0;i<=mx1;i++)
            for (j=0;j<ss;j++)
            {
                if (dp[i][j]==2e9)continue;
                x=dp[i][j];
                for (k=1;k<=m;k++)
                {
                    if (p[k]<=i)continue;
                    now=min(ss,j+p[k]-i);
                    dp[i][now]=min(dp[i][now],x+K[k]);
                }
            }
        for (i=0;i<=mx1;i++)
            for (j=ss-1;j>=0;j--)
                dp[i][j]=min(dp[i][j],dp[i][j+1]);
        sum=0;ok=0;
        for (i=1;i<=n;i++)
        {
            if (dp[b[i]][a[i]]==2e9){ok=1;continue;}
            sum+=dp[b[i]][a[i]];
        }
        if (ok) puts("-1");else printf("%I64d\n",sum);
    }
}