#include<bits/stdc++.h>
using namespace std;
#define ll long long
inline void read(int &x)
{
    x=0;
    char ch=getchar();
    while(ch<'0'||ch>'9')
        ch=getchar();
    while(ch>='0'&&ch<='9')
    {
        x=x*10+ch-'0';
        ch=getchar();
    }
}
const int N=100005,M=2005;
int n,m,x[N],y[N],a[M],v[M],f[12][M],ma1,ma2;
ll ans;
int main()
{
    //freopen("bdt3.in","r",stdin);
    //freopen("bdt3.out","w",stdout);
    while (~scanf("%d%d",&n,&m))
    {
        memset(f,0x3f,sizeof(f));
        ma1=0;
        ma2=0;
        for (int i=1;i<=n;++i)
        {
            read(x[i]);
            read(y[i]);
            ma1=max(ma1,y[i]);
        }
        for (int i=1;i<=m;++i)
        {
            read(v[i]);
            read(a[i]);
            ma2=max(ma2,a[i]);
        }
        if (ma2<=ma1)
        {
            puts("-1");
            continue;
        }
        for (int i=0;i<=10;++i)
        {
            f[i][0]=0;
            for (int j=1;j<=m;++j)
                if (a[j]>i)
                    for (int k=a[j]-i;k<=2000;++k)
                        f[i][k]=min(f[i][k],f[i][k-a[j]+i]+v[j]);
            for (int j=2000;j;--j)
                f[i][j]=min(f[i][j],f[i][j+1]);
        }
        ans=0;
        for (int i=1;i<=n;++i)
            ans=ans+f[y[i]][x[i]];
        printf("%I64d\n",ans);
    }
    return 0;
}