(N, M), *ABs = readlines.map{_1.split.map(&:to_i)}

@p = Array.new(N + 1, -1)

def root(x)
  @p[x] < 0 ? x : @p[x] = root(@p[x])
end

def unite(x, y)
  x, y = root(x), root(y)
  if x != y
    x, y = y, x if @p[y] < @p[x]
    @p[x] += @p[y]
    @p[y] = x
  end
end

ABs.each{unite(_1, _2)}
puts -@p.drop(1).min