#include<bits/stdc++.h>
using namespace std ;
#define ll long long
#include "hack.h"
const int N = 1e6 ;
ll calc ( int mid )
{
ll total = 0 ;
for ( int i = 1 ; i <= mid ; i ++ )
{
int x ;
if ( N % mid == 0 ) x = N / mid ;
else x = N / mid + ( N % mid <= i ) ;
total += 1ll*x*(x-1)/2 ;
}
return total ;
}
int hack ()
{
vector<ll> v ;
for ( int i = 1 ; i <= N ; i ++ ) v . push_back (i) ;
ll result = collisions ( v ) ;
int l = 1 , r = 1e6 ;
int res = 0 ;
while ( l <= r )
{
int mid = (l+r)/2 ;
if ( calc (mid) >= result ) l = mid + 1 , res = mid ;
else r = mid - 1 ;
}
return res ;
}
