title: How can i find unique record in python by row count?
body: <p>df:</p>
  
  <pre><code>  Country  state      item 
  0 Germany  Augsburg   Car
  1 Spain    Madrid     Bike
  2 Italy    Milan      Steel
  3 Paris    Lyon       Bike
  4 Italy    Milan      Steel
  5 Germany  Augsburg   Car
  </code></pre>
  
  <p>In the above dataframe, if we take unique record Appearance.</p>
  
  <pre><code>  Country  state      item  Appeared
  0 Germany  Augsburg   Car     1
  1 Spain    Madrid     Bike    1
  2 Italy    Milan      Steel   1
  3 Paris    Lyon       Bike    1
  4 Italy    Milan      Steel   2
  5 Germany  Augsburg   Car     2
  </code></pre>
  
  <p>Since row no. 4 and 5 appeared for the second time, i want to change their item name to differentiate both record.If a record is appeared more than once in the data, item name should be rename as Item_A for 1st appearance and Item_B for the second appearance...
  Output:</p>
  
  <pre><code>Country  state      item  Appeared
  0 Germany  Augsburg   Car_A   1
  1 Spain    Madrid     Bike    1
  2 Italy    Milan      Steel_A 1
  3 Paris    Lyon       Bike    1
  4 Italy    Milan      Stee_B  2
  5 Germany  Augsburg   Car_B   2
  </code></pre>