n=int(input())
one_num=1
two_num=1
for i in range(3,n+1):
    new_num=one_num+two_num
    two_num=one_num
    if new_num>1000000007:
        one_num=new_num%(1000000007)
    else:
        one_num = new_num

print(one_num)