To run this program, you can use one of two approaches - 1. Use the bundled ant script to compile and execute the program. $ ant -Di=inputfile.in -Do=outputfile.out -s 2. The same as above but you save the file names in the build.properties file (also bundled) 3. Compile the java file, and execute the class as: $ java rja.codejam.qual2.Watersheds inputfile.in outputfile.out