class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

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

    def get_size(self, x):
        x = self.find(x)
        return self.size[x]


N, M = map(int, input().split())
A, B = [0] * M, [0] * M
U = UnionFind(2 * N)
for i in range(M):
    A[i], B[i] = map(int, input().split())
    A[i], B[i] = A[i] - 1, B[i] - 1
    U.union(A[i], B[i])
    
S = set()
ans = 0
for i in range(2 * N):
    v = U.find(i)
    if v in S:
        continue
    S.add(v)
    ans += U.get_size(i) % 2
    
print(ans // 2)