'''
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'''
piViertel = 1 #Anfangswert
#Leibniz Formel pi/4 = 1-1/3+1/5-1/7+1/9...
nenner = 1
minus = True
for i in range(10000):
nenner += 2
if minus:
piViertel -= (1/nenner)
minus = False
elif not minus:
piViertel += (1/nenner)
minus = True
print("PI: ")
print(piViertel*4)