# Uses python3

import sys


def explore(adj, visited, v):
    visited.append(v)
    for i in adj[v]:
        if i not in visited:
            explore(adj, visited, i)


def number_of_components(adj):
    visited = []
    cc = 0
    for v in range(len(adj)):
        if v not in visited:
            explore(adj, visited, v)
            cc = cc + 1
    return cc


if __name__ == '__main__':
    input = sys.stdin.read()
    data = list(map(int, input.split()))
    n, m = data[0:2]
    data = data[2:]
    edges = list(zip(data[0:(2 * m):2], data[1:(2 * m):2]))
    adj = [[] for _ in range(n)]
    for (a, b) in edges:
        adj[a - 1].append(b - 1)
        adj[b - 1].append(a - 1)
    print(number_of_components(adj))