a,b=map(int,input().split())
# 5分/60=1/12分
a*=5*720
a+=b*(720*5//60)
b*=720
ans=0
mod=43200
na,nb=a,b
#na,nb=a%mod,b%mod
pre=na>nb
if na%mod==nb%mod:
  print(0)
  exit()
#print((a,b),pre)
for i in range(3600):
  na=a+i
  nb=b+i*(720//60)
  #na,nb=na%mod,nb%mod
  if pre!=(na>=nb):break
  ans=i
print(ans)