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f = [0] * 1000000

f[2] = 1

f[3] = 1

f[4] = 2

n = int(input())

for x in range(5, 1000000):

        if x > n: break;

        f[x] = (f[x-2] + f[x-3] + f[x-4]) % 10000000007;

print(f[n])