#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
N = int(read())
MOD = 10**9 + 7

# %%
dp_1 = [0] * (N + 10)
dp_2 = [0] * (N + 10)
dp_3 = [0] * (N + 10)

# %%
dp_1[1] = dp_2[2] = dp_3[3] = 1
for n in range(1, N):
    a, b, c = dp_1[n], dp_2[n], dp_3[n]
    a %= MOD
    b %= MOD
    c %= MOD
    dp_1[n + 1] += b + c
    dp_2[n + 2] += a + c
    dp_3[n + 3] += a + b

# %%
answer = dp_1[N] + dp_2[N] + dp_3[N]
answer %= MOD
print(answer)