#include <stdio.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string.h>

using namespace std;
int a[100005],b[100005];
int k[1005],p[1005];
long long dp[11][100005];
int main()
{
    //freopen("in.txt","r",stdin);
    int n,m;
    while(~scanf("%d%d",&n,&m))
    {
        int maxb = 0;
        for(int i=0; i<n; i++)
        {
            scanf("%d%d",&a[i],&b[i]);
            maxb = max(maxb,b[i]);
        }
        int maxp = 0;
        for(int i=0; i<m; i++)
        {
            scanf("%d%d",&k[i],&p[i]);
            maxp = max(maxp,p[i]);
        }
        if(maxp<=maxb)
        {
            printf("-1\n");
            continue;
        }
        memset(dp,0x3f,sizeof(dp));
        long long inf = dp[0][0];
        for(int x=0; x<=10; x++)
        {
            dp[x][0] = 0;
            for(int i=0; i<m; i++)
            {
                for(int j=1; j<=1000; j++)
                {
                    if(p[i]>x)
                    {
                        int temp = j-p[i]+x>0?j-p[i]+x:0;
                        dp[x][j] = min(dp[x][j],dp[x][temp]+k[i]);
                        //cout<<i<<" "<<j<<" "<<x<<" "<<dp[x][j]<<endl;
                    }
                    else break;
                }
            }
        }

        long long ans = 0;
        bool flag = true;
        for(int i=0; i<n; i++)
        {
            ans+=dp[b[i]][a[i]];
            //cout<<dp[b[i]][a[i]]<<endl;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}