Supermarket

#include <iostream>
#include <queue>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
#define maxn 11115
int n,mxx,j,ans,fa[maxn];
struct node
{
    int profit,day;
} a[maxn];
int fond(int x)
{
    return -1==fa[x]?x:fa[x]=fond(fa[x]);
}
bool cmp(node x,node y)
{
    return x.profit>y.profit;
}
int main()
{
    while(cin>>n)
    {
        memset(fa,-1,sizeof(fa));
        for(int i=0; i<n; i++)
            cin>>a[i].profit>>a[i].day;
        sort(a,a+n,cmp);
        ans=0;
        for(int i=0; i<n; i++)
        {
            j=fond(a[i].day);
            if(j>0)
            {
                ans+=a[i].profit;
                fa[j]=j-1;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}