import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c for j in range(b)] for i in range(a)]
def list3d(a, b, c, d): return [[[d for k in range(c)] for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e for l in range(d)] for k in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10**9)
INF = 10**19
MOD = 10**9 + 7
EPS = 10**-10

N = INT()

dp0 = [0] * (N+1)
dp1 = [0] * (N+1)
dp2 = [0] * (N+1)
dp0[1] = 1
if N >= 2:
    dp1[2] = 1
if N >= 3:
    dp2[3] = 1
for i in range(1, N):
    dp0[i+1] += dp1[i] + dp2[i]
    dp0[i+1] %= MOD
    if i+2 <= N:
        dp1[i+2] += dp0[i] + dp2[i]
        dp1[i+2] %= MOD
    if i+3 <= N:
        dp2[i+3] += dp0[i] + dp1[i]
        dp2[i+3] %= MOD
ans = (dp0[N] + dp1[N] + dp2[N]) % MOD
print(ans)