#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn=1100;
int read(){
    int x=0,f=1;char ch=getchar();
    while(!isdigit(ch)){
        if(ch=='-') f=-1;
        ch=getchar();
    }
    while(isdigit(ch)){
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f; 
}
int n,m,a[maxn*100],b[maxn*100],k[maxn],p[maxn],dp[maxn][12];
signed main(){
    while(cin>>n>>m){
        for(int i=1;i<=n;++i){
            a[i]=read();
            b[i]=read();
        }
        for(int j=1;j<=m;++j){
            k[j]=read();
            p[j]=read();
        }
        memset(dp,0x3f,sizeof(dp));
        int num=dp[0][0];
        for(int i=0;i<=1000;++i){
            for(int j=0;j<=10;++j){
                if(i==0) dp[i][j]=0;
                else{
                    for(int c=1;c<=m;++c){
                        if(p[c]<=j) continue;
                        else if(p[c]-j>=i){
                            dp[i][j]=min(dp[i][j],k[c]);
                        }
                        else dp[i][j]=min(dp[i][j],dp[i-(p[c]-j)][j]+k[c]);
                    }
                }
            }
        }
        int ans=0;
        bool juge=false;
        for(int i=1;i<=n;++i){
            if(dp[a[i]][b[i]]==num){
                cout<<-1<<"\n";
                juge=true;
                break;
            }
            ans+=dp[a[i]][b[i]];
        }
        if(juge) continue;
        else cout<<ans<<"\n";
    }
}