C++ :

#include<iostream>
#include<algorithm>
using namespace std;

const int N = 51;
int available[N], number[N];

int main()
{
	int n, k, p;
	int i, color, money;
	long long ans = 0;
	
	cin >> n >> k >> p;
	for (i = 1; i <= n; i++)
	{
		cin >> color >> money;
		if (money <= p) copy(number, number + N, available);
		ans += available[color];
		if (money <= p) available[color]++;
		number[color]++;
	}
	
	cout << ans << endl;
	
	return 0;
}

Pascal :

var  
  a,b:array[0..50] of longint;  
  i,j,k,m,n,s,t:longint;  
begin  
  readln(n,k,m);  
  j:=0;
	fillchar(a,sizeof(a),0);
  for i:=1 to n do  
  begin  
    readln(s,t);  
    a[s]:=a[s]+1;  
    if t<=m then  
    begin  
      b:=a;  
      j:=j+b[s]-1;  
    end else j:=j+b[s];  
  end;  
  write(j);  
end.