#include<bits/stdc++.h>
typedef long long ll;
using namespace std;
int INF = 1e9;
int MOD = 1e9+7;
ll num[] = {1,3,5,15,17,51,85,255,257,771,1285,3855,4369,13107,21845,65535,65537,196611,327685,983055,1114129,3342387,5570645,16711935,16843009,50529027,84215045,252645135,286331153,858993459,1431655765};
main(){
    set<ll> st;
    for(ll i = 0;i < 31;i++){
        for(ll j = 0;j < 32;j++){
            if(num[i] * (1 << j) <= 0)continue;
            st.insert(num[i] * (1 << j));
        }
    }
    ll N,i = -2;
    cin >> N;
    for(auto itr = st.begin();itr != st.end();itr++,i++){
        if(*itr > N){
            cout << i << endl;
            return 0;
        }
    }
}