#include <stdio.h>

int n, m, nr;
int s[100001];
int i, j, k;
typedef struct nod {
    int vf; 
    nod* urm;
} NOD, *PNOD;
PNOD l[100001];

void Add(int i, int j);
void DF(int nod);

int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for ( k = 1; k <= m; k++ )
        scanf("%d %d", &i, &j),
        Add(i, j), Add(j, i);
    
    for ( i = 1; i <= n; i++ )
        if ( !s[i] )
        {
            nr++;
            DF(i);
        }
    printf("%d\n", nr);
    
    return 0;
}

void Add(int i, int j)
{
    PNOD q = new NOD;
    q->vf = j;
    q->urm = l[i];
    l[i] = q;
}

void DF(int nod)
{
    if ( s[nod] ) return;
    s[nod] = 1;
    for ( PNOD q = l[nod]; q; q = q->urm )
        if ( !s[q->vf] )
            DF(q->vf);
}