# coding: utf-8
N = int(input())

old_first_ken = 1
old_second_ken = 0
old_pa = 0

new_first_ken = 0
new_second_ken = 0
new_pa = 0

for i in range(1, N):
    new_first_ken = old_pa
    new_second_ken = old_first_ken
    new_pa = (old_first_ken + old_second_ken) % 1000000007

    old_first_ken = new_first_ken
    old_second_ken = new_second_ken
    old_pa = new_pa

print((old_first_ken + old_second_ken + old_pa) % 1000000007)