import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int m=sc.nextInt();
        int T=sc.nextInt();
        int N=100010;
        int score[]=new int[N];
        int last[]=new int[N];
        boolean st[]=new boolean[N];
        Node order[]=new Node[N];
        for(int i=0;i<m;i++){
            int a=sc.nextInt();
            int b=sc.nextInt();
            order[i]=new Node(a,b);
        }
        Arrays.sort(order,0,m);
        for(int i=0;i<m;i++){
            int j=i; //找相同订单处理·
            while(j<m&&order[j].equals(order[i])) j++;
            int id=order[i].y,t=order[i].x,cnt=j-i;
            i=j-1; //处理一段相同订单
            score[id]-=t-last[id]-1;
            if(score[id]<0) score[id]=0; //负数可能导致答案变小，而且也不能是负数
            if(score[id]<=3) st[id]=false;
            score[id]+=cnt*2;
            if(score[id]>5) st[id]=true;
            last[id]=t;
        }
        int res=0;
        for(int i=1;i<=n;i++){
            if(last[i]<T){
                score[i]-=T-last[i];
                if(score[i]<=3) st[i]=false;
            }
            if(st[i]) res++;
        }
    System.out.println(res);
    }
    static class Node implements Comparable<Node>{
        int x,y;
        Node(int a,int b){
            x=a;y=b;
        }
        public int compareTo(Node o1){
            if(this.x==o1.x) return this.y-o1.y;
            return this.x-o1.x;
        }
        public boolean equals(Node o1){
            return x==o1.x&&y==o1.y;
        }
    }
}