d = {"H": 1, "C": 12, "N": 14, "O": 16} s = input() ans=0 i = 0 while i < len(s): k = d[s[i]] if i + 1 < len(s) and s[i + 1] not in "HCNO": k *= int(s[i+1]) i+=1 i+=1 ans+=k print(ans)