#include<stdio.h>
#include<stdlib.h>
#define max 100000
long * a[max];
unsigned int n,nr=0,viz[max];
long m;
void citire()
{scanf("%d%ld",&n,&m);
for(unsigned int i=1;i<=n;i++)
{a[i]=(long *)realloc(a[i],sizeof(long));
a[i][0]=0;
}
unsigned int x,y;
for(long i=1;i<=m;i++)
{scanf("%d%d",&x,&y);
a[x][0]++;
a[x]=(long *)realloc(a[x],(a[x][0]+1)*sizeof(long));
a[x][a[x][0]]=y;
a[y][0]++;
a[y]=(long *)realloc(a[y],(a[y][0]+1)*sizeof(long));
a[y][a[y][0]]=x;
}
}
void df(int x)
{viz[x]=1;
for(long i=1;i<=a[x][0];i++)
	if(!viz[a[x][i]])
		df(a[x][i]);
}
int main()
{freopen("dfs.in","r",stdin);
freopen("dfs.out","w",stdout);
citire();
for(unsigned int i=1;i<=n;i++)
	if(!viz[i])
	{nr++;
	df(i);
	}
printf("%d",nr);
return 0;
}