#include <fstream>
#include <vector>
using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector<int> v[100001];

void dfs(int x)
{
    v[x][0]=1;
    for(int i=1;v[x].begin()+i!=v[x].end();++i)
        if(v[v[x][i]][0]==0)
            dfs(v[x][i]);
}

int main()
{
    int n,m,i,x,y;
    fin>>n>>m;
    for(i=1;i<=n;++i)
        v[i].push_back(0);
    for(;m;m--)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;++i)
        if(v[i][0]==0)
        {
            dfs(i);
            m++;
        }
    fout<<m;
}