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

DP=[[0,0,0] for _ in range(N+1)]
DP[0][0]=1
for i in range(1,N+1):
    DP[i][0]=(DP[i-1][1]+DP[i-1][2])%Mod
    DP[i][1]=DP[i-1][0]
    DP[i][2]=DP[i-1][1]

print(sum(DP[-1])%Mod)