from collections import deque

n,m = map(int, input().split())

g = [[] for _ in range(2*n)]

for _ in range(m):
  a,b = map(int, input().split())
  a,b = a-1,b-1
  g[a].append(b)
  g[b].append(a)
  
c = [-1 for _ in range(2*n)]
cnow = 0
for i in range(2*n):
  if(c[i]!=-1):
    continue
    
  c[i] = cnow
  d = deque([i])
  while(d):
    now = d.pop()
    for v in g[now]:
      if(c[v]==-1):
        d.append(v)
        c[v] = cnow
  cnow+=1
  
count = [0 for _ in range(cnow)]
for i in c:
  count[i]+=1
  
for i in range(cnow):
  count[i]%=2
  
ans = sum(count)//2
print(ans)