As salam o alaikum

I just paid the CSS challan today (Rs. 2200/=) at one of the NBP's branches. They took the challan form and in return they gave me a CPR (computerized payment receipt), which they said includes a "CHALLAN/TREASURY number". I came home to fill the "ONLINE APPLICATION FORM", but I wasn't able to enter the challan number. The challan number i have has 14 digits, whereas, I cannot write more than 6 digits in the online application form. Kindly help me if somebody has any information or any suggestions. Please. I am worried a lot. Thank You.