N = input()
MOD = 10**9 + 7

#ans_ken1 = [0] * (N+3)
#ans_ken2 = [0] * (N+3)
#ans_pa   = [0] * (N+3)

ans_ken1 = 1
ans_ken2 = 0
ans_pa   = 0

for loop in xrange(N-1):
    ans_ken1, ans_ken2, ans_pa = ans_pa, ans_ken1, (ans_ken1+ans_ken2)%MOD

print (ans_ken1 + ans_ken2 + ans_pa) % MOD