N = int(input())
A = list()
if N == 1:
    ans = 1
elif N == 2:
    ans = 2
elif N == 3:
    ans = 2
else:
    A = [0,1,2,2]
    for i in range(4,N+1):
        var = int(A[i-3]) + int(A[i-2])
        A.append(var)
    ans = var % (10**9 + 7)
    print(ans)