#include<stdio.h>
int s[50], a[50][50], n,m, c=0;
void graf(int nod){
    s[nod] = 1;   
    for (int i = 1; i <= n; i++)
		if (!s[i] && a[nod][i]) 
			graf(i);  
}
int main(){
	int x, y;
	freopen("dfs.in","r",stdin);   
    freopen("dfs.out","w",stdout);   
    scanf("%d %d",&n,&m);
	for (int i = 1; i <= m; i++){ 
		scanf("%d %d",&x,&y);   
        a[x][y] = a[y][x] = 1;   
    }   
	for (int i = 1; i <= n; i++) 
		if (!s[i]) { 
			c++; 
			graf(i);
		}   
    printf("%d\n",c);   
    return 0;   
}