proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  while true:
    let k = getchar_unlocked()
    if k < '0': break
    result = 10 * result + k.ord - '0'.ord

const MOD = 1000000007
let n = scan()
var dp1 : array[1000001,int32]
var dp2 : array[1000001,int32]
var dp3 : array[1000001,int32]
dp1[1] = 1
dp2[2] = 1
dp1[3] = 1
dp2[3] = 1
dp3[3] = 1
for i in 4..n:
  dp1[i] = (dp1[i] + dp2[i-1] + dp3[i-1]) mod MOD
  dp2[i] = (dp2[i] + dp1[i-2] + dp3[i-2]) mod MOD
  dp3[i] = (dp3[i] + dp2[i-3] + dp1[i-3]) mod MOD
echo (dp1[n] + dp2[n] + dp3[n]) mod MOD