#include<bits/stdc++.h> 
#define N 100010
using namespace std;
int n,m,a[N],b[N],c[N],d[N],f[20][N],i,j,k;
long long ans;
int main(){
    int T=100;
    while(scanf("%d%d",&n,&m)!=EOF){
        ans=0;
        for(i=1;i<=n;i++)scanf("%d%d",&a[i],&b[i]);
        for(i=1;i<=m;i++)scanf("%d%d",&c[i],&d[i]);
        memset(f,63,sizeof(f));
        for(i=0;i<=10;i++)f[i][0]=0;
        for(i=0;i<=10;i++)
            for(j=1;j<=m;j++)if(d[j]>i)
                for(k=1;k<=1000;k++)
                    f[i][k]=min(f[i][k],f[i][max(0,k-d[j]+i)]+c[j]);
        for(i=1;i<=n;i++)
        {
            if(f[b[i]][a[i]]>1e9)ans=-1e18;
            ans+=f[b[i]][a[i]];
        }
        printf("%I64d\n",ans>=0?ans:-1);
    }
}