main = -> {
  n, m = read_line.split.map &.to_i64
  c = read_line.split.map &.to_i64.pred
  sizes = c.tally
  graph = Array.new(n) { |color| Array(Array(Int64)).new(sizes[color]? || 0) { [] of Int64 } }
  hash = Array.new(n) { Hash(Int64, Int32).new }
  m.times do
    u, v = read_line.split.map &.to_i64.pred
    if c[u] == c[v]
      color = c[u]
      hash[color][u] = hash[color].size unless hash[color].has_key?(u)
      hash[color][v] = hash[color].size unless hash[color].has_key?(v)
      u2 = hash[color][u]
      v2 = hash[color][v]
      graph[color][u2] << v2
      graph[color][v2] << u2
    end
  end
  
  ans = n.times.sum { |color|
    next 0_i64 if sizes.fetch(color, 0_i64) == 0
    ut = NgLib::DisjointSet.new(sizes.fetch(color, 0_i64))
    graph[color].each_with_index do |edges, u|
      edges.each do |v|
        ut.unite(u, v)
      end
    end
    ut.groups.size - 1
  }
  
  puts ans
}

main.call

module NgLib
  class DisjointSet
    @n : Int32
    @parent_or_size : Array(Int32)
  
    def initialize
      @n = 0
      @parent_or_size = Array(Int32).new
    end
  
    def initialize(size : Int)
      @n = size.to_i32
      @parent_or_size = [-1] * size
    end
  
    def unite(a : Int, b : Int) : Int32
      x = leader(a)
      y = leader(b)
      return x if x == y
      if -@parent_or_size[x] < -@parent_or_size[y]
        x, y = y, x
      end
      @parent_or_size[x] += @parent_or_size[y]
      @parent_or_size[y] = x
      x
    end
  
    def equiv?(a : Int, b : Int) : Bool
      leader(a) == leader(b)
    end
  
    def leader(a : Int) : Int32
      return a.to_i32 if @parent_or_size[a] < 0
      @parent_or_size[a] = leader(@parent_or_size[a])
      @parent_or_size[a]
    end
  
    def size(a : Int) : Int32
      -@parent_or_size[leader(a)]
    end
  
    def groups : Array(Array(Int32)) | Nil
      leader_buf = [0] * @n
      group_size = [0] * @n
      @n.times do |i|
        leader_buf[i] = leader(i)
        group_size[leader_buf[i]] += 1
      end
      res = Array.new(@n){ [] of Int32 }
      @n.times do |i|
        res[leader_buf[i]] << i
      end
      res.delete([] of Int32)
      res
    end
  end
end