import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
mod=10**9+7
if n==1:
  print(1)
elif n==2:
  print(1)
else:
  D=[[0]*3 for _ in range(n)]
  for i in range(n):
    if i==0:
      D[i][0]=1
      D[i][1]=0
      D[i][2]=0
    elif i==1:
      D[i][0]=0
      D[i][1]=1
      D[i][2]=0
    elif i==2:
      D[i][0]=1
      D[i][1]=1
      D[i][2]=1
    else:
      D[i][0]=D[i-1][1]+D[i-1][2]
      D[i][1]=D[i-2][0]+D[i-2][2]
      D[i][2]=D[i-3][0]+D[i-3][1]
      for j in range(3):
        if D[i][j]>mod:
          D[i][j]%=mod
  print((sum(D[-1]))%mod)