n = int(input())

k1, k2, p = [0 for i in range(n+1)], [0 for i in range(n+1)], [0 for i in range(n+1)]
k1[1] = 1
for i in range(1,n):
	k1[i+1] = p[i]  % (10**9+7)
	k2[i+1] = k1[i]  % (10**9+7)
	p[i+1] = ( k1[i] + k2[i] ) % (10**9+7)

print( (k1[n] + k2[n] + p[n]) % (10**9+7) )