/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2020.08.22 17:48:54
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;

bool ok(int x) {
    if (x % 3 != 0) return false;
    vector<int> v;
    while(x) {
        v.push_back(x % 10);
        x /= 10;
    }
    for (int i = 0; i < v.size(); i++) {
        for (int j = i + 1; j < v.size(); j++) {
            if ((v[i] + v[j]) % 3 != 0) {
                return false;
            }
        }
    }
    return true;
}
int n,cnt;
void dfs(int keta, vector<int> &v) {
    if (keta == 9) {
        int p = 0;
        int k = 1;
        for (int i = 0; i < 9; i++) {
            p += k * v[i];
            k *= 10;
        }
        if (100 <= p && p <= n) {
            
            cnt++;
        }
    }
    else {
        for (int i = 0; i <= 9; i+=3) {
            v.push_back(i);
            dfs(keta+1,v);
            v.pop_back();
        }
    }
}
int main() {
    cin >> n;
    for (int i = 12; i <= min(99,n); i++) {
        if (ok(i)) cnt++;
    }
    vector<int> v;
    dfs(0,v);
    cout << cnt << endl;
    return 0;
}