#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
using namespace std;
const int N=1E5+5;
const long long inf=1E15;
int n,m,a[N],b[N],k[N],p[N];
long long ans,dp[1005][15],w;

int main()
{
    //freopen("1.in","r",stdin); freopen("1.out","w",stdout);
    while (cin>>n>>m)
    {
        for (int i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
        for (int i=1;i<=m;i++) scanf("%d%d",&k[i],&p[i]);
        for (int j=0;j<=10;j++) 
            for (int i=1;i<=1000;i++)
            {
                dp[i][j]=inf;
                for (int r=1;r<=m;r++) if (p[r]>j) 
                {
                    if (p[r]-j>=i) w=0; else w=dp[i-(p[r]-j)][j];
                    dp[i][j]=min(dp[i][j],w+k[r]);
                }
            }
        ans=0;
        for (int i=1;i<=n&&ans<=inf;i++) ans+=dp[a[i]][b[i]];
        if (ans>=inf) printf("-1\n"); else printf("%I64d\n",ans);
    }
}