#include<bits/stdc++.h>
using ll=long long;
using std::cin;
using std::cout;
using std::vector;
using std::endl;
int main(){
    int N; cin>>N;
    const int max=1e9;
    assert(10<=N&&N<=max);
    int ans=0;
    for(int i=10;i<=100;i++){
        if(i%3==0&&i<=N) ans++;
    }
    for(int i=0;i<(1<<18);i++){
        int memo=0,X=i;
        for(int j=0;j<9;j++){
            memo=memo*10+X%4*3;
            X/=4;
        }
        if(memo<=N&&memo>=100) ans++;
    }
    cout<<ans<<endl;
}