Consider an input string of numeric characters, e.g.,
1234567895793
Your task is to add thousands separators so that the output would look like
1,234,567,895,793
If the input string contains non-numeric characters, e.g.,
123q5
then you just need to print
NaN
The first line is an integer N(<=1000) indicating the number of test cases.
Each of the next N lines is a string that needs to be printed with thousands separators.
case 1 : 0 < len(string) <= 10, all characters are number
case 2 : 0 < len(string) <= 100, all characters are number
case 3 : 0 < len(string) <= 100000
case 4 : 0 < len(string) <= 100000
The output contains N lines showing the results of the N test cases.
Each line is ended with a newline character.
If the test case is a valid numeric string, then print that number with thousands separators; otherwise, print NaN.