//By SiriusRen

#include <cstdio>

using namespace std;

#define N 2000005

int n,m,k,f[N],cnt;

struct Node{int from,to;}node[N];

int find(int x){return x==f[x]?x:f[x]=find(f[x]);}

int main(){

    scanf("%d%d%d",&n,&m,&k);

    for(int i=;i<=m;i++)scanf("%d%d",&node[i].from,&node[i].to);

    for(int i=;i<=n;i++)f[i]=i;

    for(int i=;i<=m;i++){

        if(node[i].from>k&&node[i].to>k){

            int fx=find(node[i].from),fy=find(node[i].to);

            if(fx!=fy)f[fx]=fy;

            cnt++;

        }

    }

    for(int i=;i<=m;i++){

        if(node[i].from<=k||node[i].to<=k){

            int fx=find(node[i].from),fy=find(node[i].to);

            if(fx!=fy)f[fx]=fy,cnt++;

        }

    }printf("%d\n",m-cnt);

}