#include<cstdio>
#include<vector>
using namespace std;
#define N 100001
#define pb push_back
int n,m,u[N],c,i,x,y,g[N];
vector<int> v[N];
void D(int i)
{
    int j;
	for(u[i]=1,j=0;j<g[i];j++)
        if(!u[g[i][j]])
            D(g[i][j]);
}
int main()
{
    freopen("dfs.in","r",stdin),freopen("dfs.out","w",stdout),scanf("%d%d",&n,&m);
	while(m--)
		scanf("%d%d",&x,&y),v[x].pb(y),v[y].pb(x);
    for(i=1;i<=n;i++)
		g[i]=v[i].size();
	for(i=1;i<=n;i++)
        if(!u[i])
            c++,D(i);
	printf("%d",c);
}