class UnionFind:
    def __init__(
        self,
        n: int,
    ) -> None:
        self.forest = [-1] * n

    def union(self, x: int, y: int) -> None:
        x = self.findRoot(x)
        y = self.findRoot(y)
        if x == y:
            return
        if self.forest[x] > self.forest[y]:
            x, y = y, x
        self.forest[x] += self.forest[y]
        self.forest[y] = x

    def findRoot(self, x: int) -> int:
        if self.forest[x] < 0:
            return x
        else:
            self.forest[x] = self.findRoot(self.forest[x])
            return self.forest[x]

    def issame(self, x: int, y: int) -> bool:
        return self.findRoot(x) == self.findRoot(y)

    def size(self, x: int) -> int:
        return -self.forest[self.findRoot(x)]


n, m = map(int, input().split())
ab = [tuple(map(int, input().split())) for _ in range(m)]

uf = UnionFind(n * 2)
for a, b in ab:
    uf.union(a - 1, b - 1)

groups = []
for i in range(n * 2):
    if i == uf.findRoot(i):
        groups.append(uf.size(i))

ans = 0
for g in groups:
    ans += g % 2

print(ans // 2)