Lista 3 - 1.31

#This algorithm was crated by Lucas Pereira Torres de Araujo
#Lista 3 - FUP's Class - 2016.1
#Item 1.31

s = 0

for i in xrange(1, 4):
    i = float(i)
    if i%2 == 0:
        s -= 1/(i+2) #PAR
    else:
        s += 1/(i+1) #IMPAR

print "S =", s