/*
 * @Author: mengdaoshizhongxinyang
 * @Date: 2020-11-01 10:56:21
 * @Description: 
 */
#include <iostream>
#include <vector>
#include <algorithm>
#include <string.h>
#include <map>
#include <queue>
using namespace std;
int main(){
    int n,m;
    int dp[1005][11];
    while(cin>>n){
        long long ans=0;
        for(int i=0;i<11;i++){
            for(int j=0;j<1005;j++){
                dp[j][i]=INT_MAX;
            }
        }
        for(int i=0;i<11;i++){
            dp[0][i]=0;
        }
        int a[100005];
        int b[100005];
        int mb=0;
        cin>>m;
        int k[1005];
        int p[1005];
        int mp=0;
        for(int i=0;i<n;i++){
            scanf("%d %d",&a[i],&b[i]);
            mb=max(b[i],mb);
        }
        for(int i=0;i<m;i++){
            scanf("%d %d",&k[i],&p[i]);
            mp=max(p[i],mp);
        }
        int md[11];
        if(mb>=mp){
            cout<<-1<<endl;
            continue;
        }
        memset(md,0,sizeof(md));
        for(int i=0;i<n;i++){
            if(md[b[i]]>=a[i]){
                ans+=dp[a[i]][b[i]];
            }else{
                for(int j=md[b[i]]+1;j<=a[i];j++){
                    for(int s=0;s<m;s++){
                        if(p[s]>b[i]){
                            if(j>=p[s]-b[i]){
                                dp[j][b[i]]=min(dp[j-p[s]+b[i]][b[i]]+k[s],dp[j][b[i]]);
                            }else{
                                dp[j][b[i]]=min(dp[0][b[i]]+k[s],dp[j][b[i]]);
                            }
                        }
                        
                    }
                }
                md[b[i]]=a[i];
                ans+=dp[a[i]][b[i]];
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}