n = int(input())
o = 10**9+7
pattern =[1, 1, 1] # n = 4のとき

if n == 1:
    print(1)
elif n == 2 or n == 3:
    print(2)
elif n == 4:
    print(3)
else:
    for i in range(n - 4):
        a,b,c = map(int, [x for x in pattern])
        pattern[0] = (b + c) % o
        pattern[1] = a
        pattern[2] = b
    print(sum(pattern) % o)