options formdlim = '-' nodate;

data brome;
  infile 'brome.txt';
  input freeway stream trt $ y;
  
proc glm;
  class freeway stream trt;
  model y = freeway stream trt;
  
  lsmeans trt / pdiff adjust = tukey;
  
  estimate 'uncut - rest' trt -1 -1 3 -1 / divisor = 3;
  contrast 'uncut - rest' trt -1 -1 3 -1;
  
  title 'Analysis of Latin Square, with tukey mcp to separate means';