#Given a string, output its longest prefix which contains only digits.

#Example

#For inputString="123aa1", the output should be
#longestDigitsPrefix(inputString) = "123".

def longestDigitsPrefix(inputString):

	lista = list(inputString)

	for i in range(len(inputString)):
		if not inputString[i].isnumeric():
			return inputString[0:i]
	return inputString