#include<cstdio>
const int N=100001,M=200000;
int n,m,u[N],c,i,x[M],y[M],g[N],*v[N];
void D(int i)
{
    int j;
	for(u[i]=1,j=0;j<g[i];j++)
        if(!u[v[i][j]])
            D(v[i][j]);
}
int main()
{
    freopen("dfs.in","r",stdin),freopen("dfs.out","w",stdout),scanf("%d%d",&n,&m);
    for(i=0;i<m;++i)
		scanf("%d%d",x+i,y+i),++g[x[i]],++g[y[i]];
	for(i=1;i<=n;g[i++]=0)
		v[i]=new int[g[i]];
	for(i=0;i<m;++i)
		v[x[i]][g[x[i]]++]=y[i],v[y[i]][g[y[i]]++]=x[i];
	for(i=1;i<=n;i++)
        if(!u[i])
            c++,D(i);
	printf("%d",c);
	return 0;
}