irb(main):010:0> s => "PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5P5SPS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5" irb(main):011:1* s.scan(/.../) => ["PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "P5S", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5", "PS5"] irb(main):012:0> s.scan(/.../).uniq => ["PS5", "P5S"] irb(main):013:1* s.gsub(s.scan(/.../).uniq[0], '___') => "______________________________________________________________________________________________________________________________P5S_______________________________________________________________________________________________________________" irb(main):014:0> s.gsub(s.scan(/.../).uniq[1], '___') => "PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5___PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5PS5" irb(main):015:0> s.gsub(s.scan(/.../).uniq[0], '___').index('P') => 126