def uf_find(n,p):

    ufl = []

    while p[n] != n:
        ufl.append(n)
        n = p[n]

    for i in ufl:
        p[i] = n

    return n


def uf_union(a,b,p,rank):

    ap = uf_find(a,p)
    bp = uf_find(b,p)

    if ap == bp:
        return True
    else:

        if rank[ap] > rank[bp]:
            p[bp] = ap
            size[ap] += size[bp]
        elif rank[ap] < rank[bp]:
            p[ap] = bp
            size[bp] += size[ap]
        else:
            p[bp] = ap
            rank[ap] += 1
            size[ap] += size[bp]

        return False
N,M = map(int,input().split())
N *= 2
p = [i for i in range(N)]
rank = [0] * N
size = [1] * N
for i in range(M):
	A,B = map(int,input().split())
	A-=1
	B-=1
	uf_union(A,B,p,rank)
ans = 0
for i in range(N):
	if uf_find(i,p)==i:
		ans += size[i]%2
print (ans//2)