#include <cstdio>
#include <vector>

FILE* in;
FILE* out;


const int Q=100001;

std::vector<int> f[Q];

int nrnod,nrarc;

bool gasit[Q];

void dfs(int nod)
{
    gasit[nod]=1;
    for(int i=0; i<f[nod].size(); i++)
    {
        if(gasit[f[nod][i]]==0)
        {
            dfs(f[nod][i]);
        }
    }
}

int main()
{
    in=fopen("dfs.in","r");
    out=fopen("dfs.out","w");

    fscanf(in,"%d%d",&nrnod,&nrarc);

    if(nrarc==nrnod*(nrnod+1)/2)
    {
        fprintf(out,"1");
        return 0;
    }

    int a,b;

    for(int i=1; i<=nrarc; i++)
    {
        fscanf(in,"%d%d",&a,&b);
        f[a].push_back(b);
        f[b].push_back(a);
    }

    int rez=0;
    for(int i=1; i<=nrnod; i++)
    {
        if(gasit[i]==0)
        {
            rez++;
            dfs(i);
        }
    }
    fprintf(out,"%d",rez);
    return 0;
}