n = int(input()) dp = [[0]*3]*(n+1) dp[1][0] = 0 dp[1][1] = 1 dp[1][2] = 0 for i in range(1, n): dp[i+1][0] = dp[i][1] + dp[i][2] dp[i+1][1] = dp[i][0] dp[i+1][2] = dp[i][1] print((dp[n][0] + dp[n][1] + dp[n][2]) % 10**9+7)