#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define N 100005
#define M 2005
#define INF 2147483647
#define P(a) putchar(a)
#define LL long long
#define fo(i,a,b) for(i=a;i<=b;i++)
#define fd(i,a,b) for(i=a;i>=b;i--)
#define Max(a,b) ((a)>(b)?(a):(b))
#define Min(a,b) ((a)<(b)?(a):(b))
using namespace std;
struct note{
    LL a,b;
};note a[N];
LL i,j,n,m,l,r,x,B,ans;
LL f[M];
LL k[M],p[M],nx[N];
bool pp,bz[12];
bool cmp(note x,note y){return x.b<y.b;}
void write(LL x){
    if(x>9)write(x/10);
    P(x%10+'0');
}
LL read(){
    LL fh=0,rs=0;char ch=0;
    while((ch<'0'||ch>'9')&&(ch^'-'))ch=getchar();
    if(ch=='-')fh=1,ch=getchar();
    while(ch>='0'&&ch<='9')rs=(rs<<3)+(rs<<1)+(ch^'0'),ch=getchar();
    return fh?-rs:rs;
}
int main(){
    while (scanf("%I64d%I64d",&n,&m)!=EOF){
        memset(bz,0,sizeof(bz));
        ans=0;pp=0;
        fo(i,1,n){
            a[i].a=read();
            a[i].b=read();
            bz[a[i].b]=1;
        }
        sort(a+1,a+n+1,cmp);
        a[n+1].b=11;
        fd(i,n,1)
            if (a[i].b!=a[i+1].b) nx[i]=i+1;
                             else nx[i]=nx[i+1];
        fo(i,1,m)k[i]=read(),p[i]=read();
        l=1;
        fo(B,0,10)
        if (bz[B]){
            fo(i,0,2001)f[i]=INF;
            f[0]=0;
            fo(i,1,m){
                if (p[i]-B>0)
                fo(j,p[i]-B,2000){
                    f[j]=Min(f[j],f[j-(p[i]-B)]+k[i]);
                }
            }
            fd(j,2000,0) f[j]=Min(f[j],f[j+1]);
            fo(i,l,nx[l]-1){
                if (f[a[i].a]==INF){
                    printf("-1\n");
                    pp=1;
                    break;
                }
                ans+=f[a[i].a];
            }
            if (pp) break;
            l=nx[l];
        }
        if (!pp) write(ans),P('\n');
    }
    return 0;
}