#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <cmath>
#include <queue>
#include <cstring>
#include <string>
#include <map>
#include <set>
#include <stack>
using namespace std;
typedef long long LL;
typedef unsigned long long uLL;
const int maxn=100000+10;
const int maxm=1000+10;
const int mod=(int)1e9+7;
const int INF=0x3f3f3f3f;
const LL LINF=(1LL<<60);
const double PI=acos(-1.0);
#define mst(a,b) memset(a,b,sizeof(a))
#define rep(i,a,b) for (int i=(a);i<b;i++)
#define ALL(x) x.begin(),x.end()
#define pii pair<int,int>
#define X first
#define Y second
int a[maxn],b[maxn],p[maxm],k[maxm],dp[15][maxm];
int main(){
#ifdef local
    freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
#endif
    ios::sync_with_stdio(false); cin.tie(0);
    int n,m;
    while (cin>>n>>m){
        int mx_hp=0;
        for (int i=1;i<=n;i++) {
            cin>>a[i]>>b[i];
            mx_hp=max(mx_hp,a[i]);
        }
        for (int i=1;i<=m;i++) cin>>k[i]>>p[i];
        mst(dp,0x3f);
        for (int i=0;i<=10;i++){
            dp[i][0]=0;
            for (int l=1;l<=m;l++){
                int d=p[l]-i;
                for (int j=0;j<=mx_hp;j++){
                    if (j-d>=0) dp[i][j]=min(dp[i][j-d]+k[l],dp[i][j]); else
                        dp[i][j]=min(dp[i][j],k[l]);
                }
            }
        }
        LL ans=0;
        for (int i=1;i<=n;i++){
            if (dp[b[i]][a[i]]==INF){
                ans=-1;
                break;
            }
            ans+=dp[b[i]][a[i]];
        }
        cout<<ans<<endl;
    }
    return 0;
}