class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1]*n
        self.rank = [0]*n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def issame(self, x, y):
        return self.find(x)==self.find(y)

    def size(self, x):
        return -self.parents[self.find(x)]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.rank[x] < self.rank[y]:
            x, y = y, x
        self.parents[x] += self.parents[y]
        self.parents[y] = x
        if self.rank[x] == self.rank[y]:
            self.rank[x] += 1

    def root(self):
        return [i for i in range(self.n) if self.parents[i]<0]

n,m=map(int,input().split())
uf=UnionFind(2*n)
for _ in range(m):
	a,b=map(int,input().split())
	a-=1
	b-=1
	uf.union(a,b)

ans=0
seen=set()
for i in range(2*n):
	if i in seen: continue
	v=uf.find(i)
	seen.add(v)
	ans+=uf.size(v)%2
print(ans//2)