C++ :

#include<iostream>
#include<cstring>
#include<string>
using namespace std;
int n,k,p,sd,xf,ans=0;
int fzs[101],zs[101];
bool tb;
int main()
{
    cin>>n>>k>>p;
    for(int i=1;i<=n;i++)
    {
      cin>>sd>>xf;
      fzs[sd]++;
      if(xf<=p)
      {
        memcpy(zs,fzs,sizeof(fzs));
        ans+=zs[sd]-1;
      }
      else
        ans+=zs[sd];
    }
    cout<<ans<<endl;
    return 0;
}

Pascal :

var
  i,m,ans,t,n,k,p:longint;
  lc,w,c:array[1..200000]of longint;
  l,r:array[0..50]of longint;
procedure cal(x:longint);
var
  j:longint;
begin
  for j:=0 to k-1 do
  inc(ans,l[j]*r[j]);
  inc(ans,l[c[lc[x]]]-1);
end;
begin
  readln(n,k,p);
  t:=0;
  ans:=0;
  for i:=1 to n do
    begin
      readln(c[i],w[i]);
      if w[i]<=p
        then
          begin
            inc(t);
            lc[t]:=i;
          end;
    end;
  for i:=1 to n do
    begin
      if i<=lc[1]
        then
          inc(l[c[i]])
        else
          inc(r[c[i]]);
    end;
  cal(1);
  for i:=2 to t do
    begin
      fillchar(l,sizeof(l),0);
      for m:=lc[i-1]+1 to lc[i] do
        begin
          inc(l[c[m]]);
          dec(r[c[m]]);
        end;
      cal(i);
    end;
  writeln(ans);
end.