how to use if to check the the variable is integer

I actually what to check the value of the input if it is integer print "your account is ". and if it's not an integer then print"invalid value ". so I run the program and I entered 1.2 which is double value so it should print"invalid value" but I get an ERROR? I think the condition is wrong but I don't know how to fix it?

there is the image