#include <bits/stdc++.h>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int a[1001][1001], v[1001], n, i, j, m, X, nr;
void dfs(int X)
{
    v[X] = 1;
    for(int i = 1; i <= n; ++ i)
        if(a[X][i] == 1 && v[i] == 0)
            dfs(i);
}
int main()
{
    f >> n >> m >> X;
    while(m --)
    {
        f >> i >> j;
        a[i][j] = a[j][i] = 1;
    }
    for(i = 1; i <= n; ++ i)
        if(v[i] == 0)
        {
            nr ++;
            dfs(i);
        }
    g << nr;
    return 0;
}