#include <bits/stdc++.h>
#include <numeric>
#define REP(i, s, n) for (int i = s; i < n; ++i)
#define rep(i, n) REP(i, 0, n)
#define SORT(c) sort((c).begin(), (c).end())
#define SORT_INV(c) sort((c).begin(), (c).end(), greater<int>())

#define IINF INT_MAX
#define LLINF LLONG_MAX
#define DEBUG true
#define LL long long
#define Dev 1000000007

// sort(a.begin(), a.end(), std::greater<int>());
using namespace std;

int main()
{
    long long int n=0;
    long long int ch_num = 0;
    char ch[11] = {0};
    rep(i, 11) ch[i] = -1;
    cin >> n;
    int counter = 0;
    while (n >= ch_num)
    {
        int foo[3] = {0};
        ch[0]++;
        rep(i, 10)
        {
            if (ch[i] > 2)
            {
                ch[i] = 0;
                ch[i + 1]++;
            }
        }
        ch_num = 0;
        rep(i, 11)
        {
            if (ch[i] == 0)
            {
                ch_num += 3 * pow(10, i);
                foo[0] += 1;
            }
            if (ch[i] == 1)
            {
                ch_num += 5 * pow(10, i);
                foo[1] += 1;
            }
            if (ch[i] == 2)
            {
                ch_num += 7 * pow(10, i);
                foo[2] += 1;
            }
        }
        if (foo[0] > 0 && foo[1] > 0 && foo[2] > 0 &&n>=ch_num) //3,5,7があるか
            counter++;
    }
    cout << counter << endl;
    return 0;
}