f = open("dfs.in", "r")
g = open("dfs.out", "w")

n, m = map(int,f.readline().split())

graph = [[] for _ in range(n + 1)]
used = [False] * (n + 1)

for _ in range(m):
    x, y = map(int,f.readline().split())
    graph[x].append(y)
    graph[y].append(x)

def dfs(node):
    used[node] = True
    for nxt in graph[node]:
        if not used[nxt]:
            dfs(nxt)

nr=0
for i in range(1, n + 1):
    if not used[i]:
        nr+= 1
        dfs(i)
g.write(str(nr)+"\n")

f.close()
g.close()