#include <cstdio>
using namespace std;

int main()
{
    long long n;
    int x = 1, y = 1, z = 1;
    scanf("%lld", &n);
    for (long long i = 3; i <= n; i ++)
    {
        x = y;
        y = z;
        z = (x + y) % 1000000007;
    }
    printf("%d", z);
    return 0;
}