I was able to use the readxl library to read the xls input directly
library("readxl")
The input excel file should be set up like this, with two columns. Where A,B are the columns and 1,2,3 are the rows
A B
pairwisecomparison p.value
1 June-Aug 0.1637
2 Nov-Aug 0.1093
3 Nov-July 0.9316