express

#include<iostream>
#include<algorithm>
using namespace std;
int n,m,s,k;

void in(int &x)
{
    char c=getchar();x=0;
    while(c<'0'||c>'9')c=getchar();
    while(c<='9'&&c>='0')x=x*10+c-'0',c=getchar();
}

void out(int x)
{
    if(x>9)out(x/10);
    putchar(x%10+'0');
}

long long f[200010];

struct tree
{
    int c[1010];    
    int l;
    int from;
}e[200010];

  bool cmp(int a,int b)
  {
      return a>b;
  }
bool b[200010];
long long ans,t,num;
int kind;

int main()
{
    freopen("express.in","r",stdin);
    freopen("express.out","w",stdout);
    in(n),in(m),in(s),in(k);
    for(int i=1;i<=m;i++)
    {
        in(kind),in(e[kind].c[++e[kind].l]);
        e[kind].c[e[kind].l]-=2;
    }
    for(int i=1;i<=n;i++)
    sort(e[i].c+1,e[i].c+e[i].l+1,cmp);
    for(int i=1;i<=n;i++)
    {
        t=0;
        for(int j=1;j<=e[i].l;j++)
        {
            t+=e[i].c[j];
            if(t>=k)
            {
                s-=j;
                e[i].from=j+1;
                ans+=t;
                break;
            }
        }
        if(t<k||s<0)
        {
            cout<<"-23333333";
            return 0;
        }
    }
    for(int i=1;i<=n;i++)
      for(int z=e[i].from;z<=e[i].l;z++)
       for(int j=s;j>=1;j--)
        f[j]=max(f[j],f[j-1]+e[i].c[z]);
         cout<<f[s]+ans;
    return 0;
}