#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int maxn = 100000+5;
const int maxm = 1000+5;
const int INF = 0x3f3f3f3f;
const int mod = 1e9+7;

int a[maxn],b[maxn];
int k[maxm],p[maxm];
int v[maxm];
int dp[11][maxm];

int main()
{
    // freopen("in","r",stdin);
    // freopen("out","w",stdout);
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        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]);
            k[i] *= -1;
        }

        for(int i=0;i<=10;++i)
        {
            for(int j=1;j<=m;++j)
            {
                v[j] = max(0,p[j] - i);
            }
            for(int j=0;j<maxm;++j)
            {
                dp[i][j] = -INF;
            }
            dp[i][0] = 0;

            for(int dpi=1;dpi<=m;++dpi)
            {
                for(int dpj=0;dpj<=1000;++dpj)
                {
                    if(dpj >= v[dpi])
                    {
                        dp[i][dpj] = max(dp[i][dpj],dp[i][dpj-v[dpi]] + k[dpi]);
                    }
                    else
                    {
                        dp[i][dpj] = max(dp[i][dpj],dp[i][0] + k[dpi]);
                    }
                }
            }
        }

        ll ans = 0;
        for(int i=1;i<=n;++i)
        {
            if(dp[b[i]][a[i]] == -INF)
            {
                ans = -1;
                break;
            }
            else
            {
                ans += abs(dp[b[i]][a[i]]);
            }
        }
        printf("%lld\n",ans);
    }
    return 0;
}