#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cstring>
#define N 100086
#define M 1086
#define inf 1000000000
#define ll long long
using namespace std;
int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
int a[N],b[N],k[M],p[M],h[M],v[M];
bool apr[20];
int f[20][M];
int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF){
        memset(apr,0,sizeof(apr));int mx=0;
        for(int i=1;i<=n;i++){
            a[i]=read();b[i]=read();
            apr[b[i]]=1;mx=max(a[i],mx);
        }
        for(int i=1;i<=m;i++){k[i]=read();p[i]=read();}
        for(int B=0;B<=10;B++)
            if(apr[B]){
                for(int i=0;i<=mx;i++)f[B][i]=inf;
                f[B][0]=0;int num=0;
                for(int i=0;i<=m;i++)
                    if(p[i]>B){
                        h[++num]=p[i]-B;h[num]=min(h[num],mx);v[num]=k[i];
                    }
                for(int i=1;i<=mx;i++)
                    for(int j=1;j<=num;j++)
                        if(h[j]>i)f[B][i]=min(f[B][i],v[j]);else f[B][i]=min(f[B][i],f[B][i-h[j]]+v[j]);
            }
        int flag=1;ll ans=0;
        for(int i=1;i<=n;i++)
            if(f[b[i]][a[i]]==inf)flag=0;else ans+=f[b[i]][a[i]];
        if(flag)cout<<ans<<endl;else puts("-1");
    }
    return 0;
}