se = float(raw_input())

s = se%60
m = (se/60)%60
h = (se/(60*60))%12

s_factor = s/60;
m_factor = m/60;
h_factor = h/12;

sm_diff = abs(s_factor - m_factor)
sm_diff = 1-sm_diff if sm_diff>0.5 else sm_diff

sh_diff = abs(s_factor - h_factor)
sh_diff = 1-sh_diff if sh_diff>0.5 else sh_diff

mh_diff = abs(m_factor - h_factor)
mh_diff = 1-mh_diff if mh_diff>0.5 else mh_diff

print(min(sm_diff, min(sh_diff, mh_diff))*360)