#include <cstdio>
#include <cstdlib>

using namespace std;

int n, m, nr;
int *a[100001];
bool checked[100001];

void dfs(int x)
{
    checked[x] = 1;

    for (int i = 1; i <= a[x][0]; ++i)
        if (!checked[a[x][i]]) dfs(a[x][i]);
}

int main()
{
    FILE *in, *out;
    in = freopen("dfs.in", "r", stdin);
    out = freopen("dfs.out", "w", stdout);

    scanf("%d%d", &n, &m);

    for (int i = 1; i <= n; ++i) {
        a[i] = (int *)realloc(a[i], sizeof(int));
        a[i][0] = 0;
    }

    while (m--) {
        int x, y;
        scanf("%d%d", &x, &y);

        ++a[x][0];
        a[x] = (int *)realloc(a[x], (a[x][0] + 1) * sizeof(int));
        a[x][a[x][0]] = y;

        ++a[y][0];
        a[y] = (int *)realloc(a[y], (a[y][0] + 1) * sizeof(int));
        a[y][a[y][0]] = x;
    }

    for (int i = 1; i <= n; ++i)
        if (!checked[i]) {
            ++nr;
            dfs(i);
        }

    printf("%d", nr);

    fclose(in);
    fclose(out);

    return 0;
}