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n = int(input()) sch = 0 k40 = [0]*40 k4030 = [0]*40 q = 0 for i in range(n): a = int(input()) b = a%40; b1 = (40 - b%40)%40 if a >= 30: sch += k40[b1] + k4030[b1] k4030[b] += 1 else: sch += k4030[b1] k40[b] += 1 print(sch)