how can i define 10^10 ? it is asking as limit but it is long rang how can i define it?
10^10 is quite within the range of built-in data types for most programming languages. For example C / C++ have long long int which ranges from -2^63 to (2^63)-1 (I am too lazy to remember or look up the decimal representation 
but it is much larger than your requirement I.e. 10^10)
In C++ for example, you can do it like this: long long x = 10000000000LL;