Revision 5c2025fe-62ae-4e90-8dc8-1616d9c1548d - Code Golf Stack Exchange

# Julia, 42 bytes - 25 = 17

<!-- language-all: lang-julia -->

 print("@"^42((r=readline())>""?int(r):2))

This reads a line from STDIN using `readline()`. If it's empty, i.e. no input has been provided, then *n* is defined to be the input converted to an integer. Otherwise *n* is 2. We then print 42​*n* `@`s to STDOUT.