#include <stdio.h>
#include <malloc.h>
#include <stdint.h>

int ptns = 0;
int n;
/// <summary>
/// 入力された数字を返す
/// </summary>
/// <returns></returns>
int ReadNum() {
	int negate = 0;
	char c = getchar();
	int num = 0;
	int numCnt = 0;
	while (c != '\n') {
		if (c == '-') {
			negate = 1;
		}
		else {
			num = num * 10 + c - '0';
		}

		c = getchar();
	}
	if (negate == 1) {
		num *= -1;
	}
	return num;
}

int main() {
	n = ReadNum();
	uint64_t* nums;
	nums = (uint64_t*)malloc(sizeof(uint64_t) * n);
	nums[0] = 1;
	nums[1] = 2;
	nums[2] = 2;
	for (int i = 3;i < n;i++) {
		nums[i] = (nums[i - 3] + nums[i - 2])% 1000000007;
	}

	printf("%llu\n",nums[n-1]);
}