a=float(input('please enter first number'))
b=float(input('please enter second number'))
if(a>b):
  print('first number is big')
else :
  print('second number is big')

Explanation:-in this program we have taken 2 floating inputs and assigned them to 2 variables a and b . after that we have applied if decision construct in python to apply our logic. If a is greater than b then control will execute statements under if construct otherwise statements in else construct will execute.  Program is self explanatory.