import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
mod=10**9+7
if n==1:
  print(1)
else:
  a,b,c=1,1,0
  for i in range(2,n):
    a,b,c=c,a+c,b
    if b>mod:
      b%=mod
  print((a+b+c)%mod)