int input ost 80 ost50 80 kpar for in range int input 80 y1 80 80 if 5

N = int(input())
ost = [0]*80
ost50 = [0]*80
kpar = 0
for i in range(N):
   x = int(input())
   y = x%80; y1 = (80 - y)%80
   if x > 50:
      kpar += ost[y1] + ost50[y1]
      ost50[y] += 1
   else:
      kpar += ost50[y1]
      ost[y] += 1
print(kpar)