class SegmentTree
  
  def initialize
    @N=2**17
    @INF=2**31-1
    @seg=Array.new(2*@N-1){@INF}
    @lazy=Array.new(2*@N-1){-1}
  end
  
  def refresh(i, l, r)
    unless @lazy[i]==-1
      @seg[i]=@lazy[i]
      if r-l>1
        @lazy[2*i+1]=@lazy[i]
        @lazy[2*i+2]=@lazy[i]
      end
      @lazy[i]=-1
    end
  end
  
  def update(a, b, x, i=0, l=0, r=@N)
    refresh(i, l, r)
    if b<=l or r<=a
      return
    elsif a<=l and r<=b
      @lazy[i]=x
      refresh(i, l, r)
    else
      m=(r+l)/2
      update(a, b, x, 2*i+1, l, m)
      update(a, b, x, 2*i+2, m, r)
      @seg[i]=[@seg[2*i+1], @seg[2*i+2]].min
    end
  end
  
  def min(a, b, i=0, l=0, r=@N)
    refresh(i, l, r)
    if b<=l or r<=a
      @INF
    elsif a<=l and r<=b
      @seg[i]
    else
      m=(r+l)/2
      vl=min(a, b, 2*i+1, l, m)
      vr=min(a, b, 2*i+2, m, r)
      [vl, vr].min
    end
  end
  
end

st=SegmentTree.new
n, q=gets.split.map(&:to_i)
q.times do
  query=gets.chomp
  case query[0].to_i
  when 0
    c, s, t, x=query.split.map(&:to_i)
    st.update(s, t+1, x)
  when 1
    c, s, t=query.split.map(&:to_i)
    puts st.min(s, t+1)
  end
end