//
// Created by yamunaku on 2020/08/22.
//

#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (n); i++)
#define repl(i, l, r) for(int i = (l); i < (r); i++)
#define per(i, n) for(int i = ((n)-1); i >= 0; i--)
#define perl(i, l, r) for(int i = ((r)-1); i >= (l); i--)
#define all(x) (x).begin(),(x).end()
#define MOD9 998244353
#define MOD1 1000000007
#define IINF 1000000000
#define LINF 1000000000000000000
#define SP <<" "<<
#define CYES cout<<"Yes"<<endl
#define CNO cout<<"No"<<endl
#define CFS cin.tie(0);ios::sync_with_stdio(false)
#define CST(x) cout<<fixed<<setprecision(x)

using ll = long long;
using ld = long double;
using vi = vector<int>;
using mti = vector<vector<int>>;
using vl = vector<ll>;
using mtl = vector<vector<ll>>;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
template<typename T>
using heap = priority_queue<T, vector<T>, function<bool(const T, const T)>>;

int main(){
    //CFS;
    ll n;
    cin >> n;
    ll ans = 0;
    vl one = {1, 4, 7};
    vl two = {2, 5, 8};
    rep(i, 3){
        rep(j, 3){
            ll tmp = one[i] * 10 + two[j];
            if(tmp % 3 == 0 && tmp <= n) ans++;
            tmp = two[i] * 10 + one[j];
            if(tmp % 3 == 0 && tmp <= n) ans++;
        }
    }
    vi c;
    while(n){
        c.push_back(n % 10);
        n /= 10;
    }
    reverse(all(c));
    vl dp(2);
    dp[0] = 1, dp[1] = 0;
    rep(i, c.size()){
        ll k = dp[0];
        if(c[i] % 3 != 0) dp[0] = 0;
        dp[1] *= 4;
        if(c[i] > 0) dp[1] += k;
        if(c[i] > 3) dp[1] += k;
        if(c[i] > 6) dp[1] += k;
        if(c[i] > 9) dp[1] += k;
    }
    cout << ans + dp[0] + dp[1] - 4 << endl;
    return 0;
}