#include<cstdio>
#include<vector>

using namespace std;

const int nmax=100005;

vector<int>g[nmax];
bool viz[nmax];

inline void dfs(int nod)
{
    if(viz[nod])
        return;
    int i,sz=g[nod].size();
    viz[nod]=1;
    for(i=0;i<sz;i++)
        dfs(i);
}

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int i,j,n,m,x,y,cnt=0;
    scanf("%d%d",&m,&n);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!viz[i])
        {
            dfs(i);
            cnt++;
        }
    printf("%d",cnt);
}