Sum the values in s for each label in the first level (totals for A, B, C).

Input

A  0     0
   1     1
   2     2
   3     3
   4     4
        ..
C  5    25
   6    26
   7    27
   8    28
   9    29
Length: 30, dtype: int64

Output

A     45
B    145
C    245
dtype: int64