Problem-3(Sharing after contest)

#include <bits/stdc++.h>

using namespace std;
//using namespace chrono;

typedef long long ll;
typedef vector< int > vi;
typedef vector< ll > V;
typedef map<int, int > mp;

#define pb push_back
#define FastIO ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define F first
#define S second

#define debug cout << -1 << endl;
#define REP(i, a, b) for(int i=a; i<b; i++)
#define f0r(i, n) for (int i = 0; i < n; ++i)
#define f0r1(i, n) for (int i = 1; i <= n; ++i)
#define r0f(i, n) for(int i=n-1; i>=0; i--)
#define r0f1(i, n) for(int i=n; i>=1; i--)
#define fore(a, x) for (auto& a : x)
#define fori(i, a, b) for (int i = (a); i < (b); ++i)

#define MP make_pair
#define UB upper_bound
#define LB lower_bound
#define nw cout << "\n"

#define issq(x) (((ll)(sqrt((x))))*((ll)(sqrt((x))))==(x))
#define rev(v) reverse(v.begin(),v.end())
#define asche cerr<<"Ekhane asche\n";
#define rev(v) reverse(v.begin(),v.end())
#define srt(v) sort(v.begin(),v.end())
#define grtsrt(v) sort(v.begin(),v.end(),greater<ll>())
#define all(v) v.begin(),v.end()
#define mnv(v) *min_element(v.begin(),v.end())
#define mxv(v) *max_element(v.begin(),v.end())
#define valid(tx,ty) (tx>=0 && tx<n && ty>=0 && ty<m)
#define one(x) __builtin_popcount(x)
//#define pop pop_back
#define setPrec(x) cout << fixed << setprecision(x)
#define sz(a) (int)a.size()
//#define fin cin
//#define fout cout
const int INF = 1e9;
const ll MOD = (ll)1e9+7;
const ll INFL = 1e18;
const ll mnINF = -1e18;
const double diff = 10e-6;
const int maxn = 500005;
const double PI = acos(-1);
using namespace std;

// int dx[] = {-1, 0, 1};
// int dy[] = {-1, 0, 1};

int dx[] = {-1, 0, 0, 1};
int dy[] = {0, -1, 1, 0};

vector< ll > v;
int arr[] = {4, 7};

void gen2()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) {
        x = arr[i]*10 + arr[j];
        v.pb(x);
    }
}

void gen3()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) {
        x = arr[i]*100 + arr[j]*10 + arr[k];
        v.pb(x);
    }
}

void gen4()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) {
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        v.pb(x);
    }
}

void gen5()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) f0r(m, 2){
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        x *= 10LL;
        x += arr[m];
        v.pb(x);
    }
}

void gen6()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) f0r(m, 2) f0r(o, 2){
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        x *= 10LL;
        x += arr[m];
        x *= 10LL;
        x += arr[o];
        v.pb(x);
    }
}

void gen7()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) f0r(m, 2) f0r(o, 2) f0r(p, 2){
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        x *= 10LL;
        x += arr[m];
        x *= 10LL;
        x += arr[o];
        x *= 10LL;
        x += arr[p];
        v.pb(x);
    }
}

void gen8()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) f0r(m, 2) f0r(o, 2) f0r(p, 2) f0r(q, 2){
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        x *= 10LL;
        x += arr[m];
        x *= 10LL;
        x += arr[o];
        x *= 10LL;
        x += arr[p];
        x *= 10LL;
        x += arr[q];
        v.pb(x);
    }
}

void gen9()
{
    ll x = 0LL;
    f0r(i, 2) f0r(j, 2) f0r(k, 2) f0r(l, 2) f0r(m, 2) f0r(o, 2) f0r(p, 2) f0r(q, 2) f0r(r, 2){
        x = arr[i]*100 + arr[j]*10 + arr[k];
        x*=10LL;
        x += arr[l];
        x *= 10LL;
        x += arr[m];
        x *= 10LL;
        x += arr[o];
        x *= 10LL;
        x += arr[p];
        x *= 10LL;
        x += arr[q];
        x *= 10LL;
        x += arr[r];
        v.pb(x);
    }
}

void solve()
{
    v.pb(4);
    v.pb(7);
    gen2(); gen3(); gen4(); gen5(); gen6(); gen7(); gen8();
    gen9();
    // for(auto xx: v) cout << xx << "\n";
    ll x;
    cin >> x;
    cout << upper_bound(v.begin(), v.end(), x)-v.begin() << "\n";
}



void setIO(string name = "") { // name is nonempty for USACO file I/O

    ios_base::sync_with_stdio(0); cin.tie(0); // see Fast Input & Output

    // alternatively, cin.tie(0)->sync_with_stdio(0);

    if (name.size()) {

        freopen((name+".in").c_str(), "r", stdin); // see Input & Output

        freopen((name+".out").c_str(), "w", stdout);

    }

}

int main()
{
    //setIO("breedflip");
    FastIO;
    int t;
    t = 1;
    // cin >> t;
    f0r(i, t) {
        //cout << "Case " << i+1 << ": ";
        solve();
    }
    return 0;
}