#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
const int inf=101;
#define MAXN 200001
int a[MAXN],b[MAXN],f[MAXN][MAXN];
int ans;
int main(){
	int n,p,k,i,j;
	scanf("%d%d%d",&n,&p,&k);
	for(i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
	for(i=1;i<=n;i++) f[i][i]=b[i];
	for(i=1;i<=n;i++){
		for(j=i+1;j<=n;j++){
			f[i][j]=min(f[i][j-1],b[j]);
			if(a[i]==a[j]&&f[i][j]<=k) ans++;
		}
	}
	printf("%d",ans);
	return 0;
}