def substitution(inputText,charSub)
		@output = ''
		charSub.each{ |key,value| charSub[key] = '_' unless value }

		charSub.each do |key, value|


			@output = inputText.gsub(key.to_s , value.to_s)

			end





		return 	@output


		end

Input:asfasdfsd
Output:
!sf!sdfsd
a_fa_df_d
as_asd_sd
asfas_fs_