power = int(input())
target = str(10 ** power)
length = len(target)
dp = [[[[0 for l in range(3)] for m in range(2)] for n in range(2)] for k in range(length + 1)]
dp[0][0][0][0] = 1
for i,t in enumerate(target):
    for flag in range(2):
        for div in range(2):
            for modu in range(3):
                limit = 9 if flag else int(t)
                for lim in range(limit + 1):
                    dp[i+1][flag or lim < int(t)][div or lim == 3][(modu * 10 + lim) % 3] += dp[i][flag][div][modu]
print(dp[length][1][1][0] + dp[length][1][1][1] + dp[length][1][1][2] + dp[length][1][0][0] - 1)