#Сы Юйхао, 1032255367,НКАбд-04-25,6.3.26, 19:45
#Найти сумму 1 - 1/3 + 1/5 - 1/7 + ... (N слагаемых)
n=int(input("n:"))
def sum(n):
s = 0.0
a = 1
b = 1
for _ in range(n):
s += a / b
a *= -1
b += 2
return s
print(sum(n))
I9Ch0Ysg0K7QudGF0LDQviwgMTAzMjI1NTM2NyzQndCa0JDQsdC0LTA0LTI1LDYuMy4yNiwgMTk6NDUKI9Cd0LDQudGC0Lgg0YHRg9C80LzRgyAxIC0gMS8zICsgMS81IC0gMS83ICsgLi4uIChOINGB0LvQsNCz0LDQtdC80YvRhSkKbj1pbnQoaW5wdXQoIm46IikpCmRlZiBzdW0obik6CiAgICBzID0gMC4wCiAgICBhID0gMQogICAgYiA9IDEKICAgIGZvciBfIGluIHJhbmdlKG4pOgogICAgICAgIHMgKz0gYSAvIGIKICAgICAgICBhICo9IC0xCiAgICAgICAgYiArPSAyCiAgICByZXR1cm4gcwpwcmludChzdW0obikp