Error in Python program when multiplying integers by fractions and decimals
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I tried to make a short program that works out the famous Drake equation. I got it to accept integer inputs, decimal inputs, and fractional inputs. However, I get this error when the program attempts to multiply them (right after I input all necessary values the error happens): 

Traceback (most recent call last)
  File "C:/Users/Family/Desktop/Programming/Python Files/1/DrakeEquation1.py", line 24, in <module>
    calc() #cal calc to execute it
  File "C:/Users/Family/Desktop/Programming/Python Files/1/DrakeEquation1.py", line 17, in calc
    calc = r*fp*ne*fl*fi*fc*l
TypeError: can't multiply sequence by non-int of type 'str'

My code can is as follows:

    def intro():
        print('This program will evaluate the Drake equation with your values')

    def calc():
        print('What is the average rate of star formation in the galaxy?')
        r = input()
        print('What fraction the stars have planets?')
        fp = input()
        ne = int(input('What is the average number of life supporting planets (per     star)?'))
        print('What fraction of these panets actually develop life')
        fl = input()
        print('What fraction of them will develop intelligent life')
        fi = input()
        print('What fraction of these civilizations have developed detectable technology?')
        fc = input()
        l = int(input('How long will these civilizations release detectable signals?'))
        calc = r*fp*ne*fl*fi*fc*l

        print('My estimate of the number of detectable civilizations is ' + calc + ' .')
                   
    
    if __name__=="__main__":
        intro() #cal intro to execute it 
        calc() #cal calc to execute it 

What do I need to change in order to fix this problem? 
