class Demo:
def rhomb(self,input):
result = ''
input = input.strip()
try:
num = float(input)
if num<0 or num>100:
result = input + '-->' + 'Error number'
elif num<60:
result = input + '-->' + 'F'
elif num<70:
result = input + '-->' + 'D'
elif num<80:
result = input + '-->' + 'C'
elif num<90:
result = input + '-->' + 'B'
else:
result = input + '-->' + 'A'
except:
result = input + '-->' + 'It is not a number'
return result
Test = Demo()
print Test.rhomb('59')
print Test.rhomb('90.5')
print Test.rhomb('23')
print Test.rhomb('60')
print Test.rhomb('75')
print Test.rhomb('e')
print Test.rhomb('-90')
print Test.rhomb('999')
print Test.rhomb(' 999 ')
print Test.rhomb('88')
print Test.rhomb('0')
