#include <fstream>
#include <vector>
#include <queue>
#define x first
#define y second
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
int i,j,d[100010],n,m,s,a,b,now,z,p;
vector <int> v[100010];
queue <int> q;
int main()
{
    fin>>n>>m>>s;
    for(i=1;i<=m;i++)
        fin>>a>>b,v[a].push_back(b);
    for(j=1;j<=n;j++){
        if(d[j]==0)
       { q.push(j);p++;d[j]=p;
        while(!q.empty())
        {
            now=q.front();
            z=v[now].size();
            for(i=0;i<z;i++)
                if(d[v[now][i]]==0)
                    d[v[now][i]]=p,q.push(v[now][i]);
            q.pop();
        }}
}
    fout<<p;
    return 0;
}