15

maxi=0
for a in range(0, 100):
  p=0
  for x in range(0, 100):
    for y in range(0, 100):
      if 2*x+y != 50 or x < y or a < x:
        p+=1
  if p==10000:
    maxi=max(maxi, a)
print(maxi)