class UnionFind:
    def __init__(self, size):
        self.parent = list(range(size + 1))  # 1-based indexing
        self.size = [1] * (size + 1)
    
    def find(self, x):
        if self.parent[x] != x:
            self.parent[x] = self.find(self.parent[x])
        return self.parent[x]
    
    def unite(self, x, y):
        x_root = self.find(x)
        y_root = self.find(y)
        if x_root == y_root:
            return
        if self.size[x_root] < self.size[y_root]:
            x_root, y_root = y_root, x_root
        self.parent[y_root] = x_root
        self.size[x_root] += self.size[y_root]

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    M = int(input[idx])
    idx += 1
    students = 2 * N
    uf = UnionFind(students)
    for _ in range(M):
        a = int(input[idx])
        idx += 1
        b = int(input[idx])
        idx += 1
        uf.unite(a, b)
    
    seen = set()
    total_remainder = 0
    for i in range(1, students + 1):
        root = uf.find(i)
        if root not in seen:
            seen.add(root)
            s = uf.size[root]
            total_remainder += s % 2
    print(total_remainder // 2)

if __name__ == "__main__":
    main()