Python elementary problem

[saratha]

In a given text you need to sum the numbers. Only separated numbers should be counted. If a number is part of a word it shouldn't be counted.

this is the problem. I'm a beginner programmer in terms of solving python logical problems. I've tried to use .isdigit but then I can't find if the numbers is separated or not. Now what must I do to solve the problem?

oh P.S: The text consists from numbers, spaces and english letters. No other signs.