var n,p,i,ii,jj,k,kk,ans:longint;

a,b:array[1..200000]of longint;

begin read(n,k,p);

for i:=1 to n do

read(a[i],b[i]);

ans:=0;

for ii:=1 to n-1 do

for jj:=ii+1 to n do

if a[ii]=a[jj] then

for kk:=ii+1 to jj-1 do

if b[kk]<=p then ans:=ans+1;

writeln(ans);

end.