pos = input()
place = pos[-1]
row1 = pos[:len(pos) - 1]
res = 0
row = int(row1)
row-=1
d = {"f":1, "e":2, "d":3, "a":4, "b":5, "c":6}
res = (row // 4) * 12
if row % 4 == 3:
    res+=4
elif row % 4 == 1:
    res+= 6
print(res + row + d[place])