#include<cstdio>
const int N=100001,M=200000,L=2000000;
int n,m,u[N],c,i,x[M],y[M],g[N],*v[N],k,l;
char r[L];
int A()
{
  	int s=0;
  	for(;r[k]<'0'||r[k]>'9';k++);
  	for(;r[k]>='0'&&r[k]<='9';k++)
  		s=s*10+r[k]-'0';
  	return s;
}
void S(int b)
{
    char e[100];
    int j;
    for(j=0;b;b/=10,j++)
        e[j]=b%10+48;
    for(j--;j>=0;j--)
        r[l++]=e[j];
}
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),fread(r,1,L,stdin),n=A(),m=A();
    for(i=0;i<m;i++)
		x[i]=A(),y[i]=A(),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);
    S(c),fwrite(r,1,l,stdout);
}