n=int(input())
m=10**9+7
d=[[0,0,0] for _ in range(n+1)]
d[1]=[0,1,0]
for i in range(2,n+1):
    d[i][0]=(d[i-1][1]+d[i-1][2])%m
    d[i][1]=d[i-1][0]%m
    d[i][2]=d[i-1][1]%m
print(sum(d[n])%m)