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