df has an integer column 'A'. Filter out rows that contain the same integer as the row immediately above. Return the filtered DataFrame.

Input

    A
0   1
1   2
2   2
3   3
4   4
5   5
6   5
7   5
8   6
9   7
10  7

Output

   A
0  1
1  2
3  3
4  4
5  5
8  6
9  7