5 3
1 2
1 3
4 5

2

import sys
sys.setrecursionlimit(10000)
n, m = map(int, input().split())
graph = [[] for _ in range(n+1)]
for _ in range(m):
    u, v = map(int, input().split())
    graph[u].append(v)
    graph[v].append(u)
visited = [False]*(n+1)
def dfs(node):
    visited[node] = True
    for nxt in graph[node]:
        if not visited[nxt]:
            dfs(nxt)
count = 0
for i in range(1, n+1):
    if not visited[i]:
        dfs(i)
        count += 1
print(count)