#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include<bits/stdc++.h>
#define ll long long 
#define pb push_back
#define bg begin()
#define en end()
#define vvl(n,m) vector<vector<ll> > a( n , vector<ll> (m))
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
using namespace std;
#define MAXN   1000001
int spf[MAXN]; 
  
// Calculating SPF (Smallest Prime Factor) for every 
// number till MAXN. 
// Time Complexity : O(nloglogn) 
void sieve() 
{ 
    spf[1] = 1; 
    for (int i=2; i<MAXN; i++) 
  
        // marking smallest prime factor for every 
        // number to be itself. 
        spf[i] = i; 
  
    // separately marking spf for every even 
    // number as 2 
    for (int i=4; i<MAXN; i+=2) 
        spf[i] = 2; 
  
    for (int i=3; i*i<MAXN; i++) 
    { 
        // checking if i is prime 
        if (spf[i] == i) 
        { 
            // marking SPF for all numbers divisible by i 
            for (int j=i*i; j<MAXN; j+=i) 
  
                // marking spf[j] if it is not  
                // previously marked 
                if (spf[j]==j) 
                    spf[j] = i; 
        } 
    } 
} 
  
// A O(log n) function returning primefactorization 
// by dividing by smallest prime factor at every step 
vector<int> getFactorization(int x) 
{ 
    vector<int> ret; 
    while (x != 1) 
    { 
        ret.push_back(spf[x]); 
        x = x / spf[x]; 
    } 
    return ret; 
} 
ll gcd(ll a,ll b){
    if(a==0)
    return b;
    else
    return gcd(b%a,a);
}
ll maxSubArraySum(ll a[], ll size) 
{ 
    ll max_so_far = -1000000000000000, max_ending_here = 0; 
  
    for (ll i = 0; i < size; i++) 
    { 
        max_ending_here = max_ending_here + a[i]; 
        if (max_so_far < max_ending_here) 
            max_so_far = max_ending_here; 
  
        if (max_ending_here < 0) 
            max_ending_here = 0; 
    } 
    return max_so_far; 
} 
ll countPairs(ll arr[], ll n) 
{ 
    map<ll, ll> map; 
    for (ll i = 0; i < n; i++) {
        if (map.find(arr[i]-i) == map.end()) { 
            map[arr[i]-i] = 1; 
        } 
        else { 
            map[arr[i]-i]++; 
        } 
    }
    ll res = 0; 
    for (auto x : map) { 
        ll cnt = x.second; 

        res += ((cnt * (cnt - 1)) / 2); 
    } 
  
    return res; 
} 
ll findSubarraySum(ll arr[], ll n, ll sum) 
{ 
    unordered_map<ll, ll> prevSum; 
  
    int res = 0; 
  
    int currsum = 0; 
  
    for (int i = 0; i < n; i++) { 
        currsum += arr[i]; 
        if (currsum == sum)  
            res++;         
  
        if (prevSum.find(currsum - sum) !=  
                                  prevSum.end())  
            res += (prevSum[currsum - sum]);
        prevSum[currsum]++; 
    } 
  
    return res; 
} 
ll sod(ll x){
    ll r,sum=0;
    while(x>0){
        r=x%10;
        x/=10;
        sum+=r;
    }
    return sum;
}
long long modpow(long long a, long long b, long long m) {
    a %= m;
    long long res = 1;
    while (b > 0) {
        if (b & 1)
            res = res * a % m;
        a = a * a % m;
        b >>= 1;
    }
    return res;
}
ll smallestSumSubarr(ll arr[], ll n) 
{ 
    ll min_ending_here = 1e18; 
    ll min_so_far = 1e18; 
      
    // traverse the array elements 
    for (ll i=0; i<n; i++) 
    { 
        // if min_ending_here > 0, then it could not possibly 
        // contribute to the minimum sum further 
        if (min_ending_here > 0) 
            min_ending_here = arr[i]; 
          
        // else add the value arr[i] to min_ending_here     
        else
            min_ending_here += arr[i]; 
          
        // update min_so_far 
        min_so_far = min(min_so_far, min_ending_here);             
    } 
      
    // required smallest sum contiguous subarray value 
    return min_so_far; 
} 
int main()
{
    fast
    ll n,i,m=1e9+7;
    cin>>n;
    ll s[n+1];
    for(i=3;i<=n;i++){
        s[i]=1;
    }
    s[0]=0;s[1]=0;s[2]=0;
    ll sum=0;
    for(i=6;i<n+1;i++){
        sum=(sum+s[i-3])%m;
        s[i]=(s[i]+sum)%m;
    }
    cout<<s[n];
}

Measured memory_bytes: 3652