recourtion

#include<bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef pair<ll,ll> pll;
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL))
#define fi first
#define se second
#define pb push_back
ll const MOD=1000000007;
#define eb emplace_back
const int N=10000005;


void call(ll n)
{
    if(n<=1)
    {
        cout<<n;
        return ;
    }

    call(n/2);

    cout<<n%2;

    return ;

}


int main()
{
ll n;
cin>>n;
  call(n);


}

''''''''''''''''''''''''''''''''

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
#define ff first
#define ss second
#define pb push_back
#define eb emplace_back
typedef pair<ll,ll>pll;
typedef pair<ll,pair<ll,ll>>plll;
const ll mod=1e9+7;
const ll Max=2e5+7;
pll ara[Max+1];
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL));
bool f;
ll tar;
void call(ll n)
{
    if(n==tar)
    {
        f=true;
        return;
    }

    if(n>tar)return;;

    call(n+3);
    call(n+7);




}


int main()
{
    fastread();

ll t;

cin>>t;
ll ara[102];
for(ll i=1;i<=100;i++)
{
      f=false;
      tar=i;

    call(0);

    if(f)ara[i]=1;
    else ara[i]=0;

}

while(t--)
{


ll a;
    cin>>a;
 if(ara[a])cout<<"YES"<<endl;
 else cout<<"NO"<<endl;

}

}
pb link :https://codeforces.com/contest/903/problem/A