#include <fstream>
#include <algorithm>
using namespace std;
ifstream cin("stalpi.in");
ofstream cout("stalpi.out");
const int lim=1e5+3;
int n,x,c,s,d;
struct segm
{
    int l,r,cost;
}v[lim];
bool mycmp(segm x,segm y)
{
    return x.l<y.l or
        (x.l==y.l and x.r<y.r) or
        (x.l==y.l and x.r==y.r and x.cost<y.cost);
}
int main()
{
    cin>>n;
    for(int i=1;i<=n;++i)
    {
        cin>>x>>c>>s>>d;
        v[i].l=x-s;
        v[i].r=x+d;
        v[i].cost=c;
    }
    sort(v+1,v+n+1,mycmp);
    int dr=v[1].r,sum=v[1].cost;
    for(int i=2;i<=n;++i)
    {
        if(v[i].l>dr)
        {
            dr=v[i].r;
            sum+=v[i].cost;
        }
    }
    cout<<sum;
    return 0;
}