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

if N == 1:
    print(1)
    exit()
    
dp0 = 1
dp1 = 0
dp2 = 1

for i in range(2, N):
    dp0, dp1, dp2 = dp1 % MOD, dp2 % MOD, (dp0 + dp1) % MOD
    
print((dp0+dp1+dp2) % MOD)