A,B = map(int, input().split())
A=A%12
s=0
while  (A*3600+B*60+s)%43200!=(B*720+s*12)%43200: 
    if ((A*3600+B*60+s)%43200-(B*720+s*12)%43200)*((A*3600+B*60+(s+1))%43200-(B*720+(s+1)*12)%43200)<0 and (B*720+(s+1)*12)%43200!=0:
        break
    s+=1
print(s)