def root(x):
    if P[x] < 0: return x
    P[x] = root(P[x])  # 経路圧縮
    return P[x]

def merge(x,y):
    x = root(x)
    y = root(y)
    if x == y: return
    if x > y: x,y = y,x
    P[x] += P[y]
    P[y] = x

def same(x,y):
    return root(x) == root(y)

def size(x):
    x = root(x)
    return -P[x]


N,M = map(int,input().split())
P = [-1] * (N * 2)
for i in range(M):
    a,b = map(int,input().split())
    a -= 1
    b -= 1
    merge(a,b)
tmp = 0

S = set()
for i in range(2 * N):
    if root(i) not in S:
        tmp += size(i) % 2
        S.add(root(i))
print(tmp//2)