x = int(input())
ans = [-1] * 15
pos = 0
t = 0
cnt = 0
lst = [2, 2, -1, -1, 2, -1, -1]
while 1:
    try:
        if ans[pos] == -1:
            ans[pos] = cnt
    except:
        break
    cnt += abs(lst[t])
    pos += lst[t]
    t += 1
    if t == 7:
        t = 0

print(ans[x])