Algorithm

A. Vanya and Cubes
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Vanya got n cubes. He decided to build a pyramid from them. Vanya wants to build the pyramid as follows: the top level of the pyramid must consist of 1 cube, the second level must consist of 1 + 2 = 3 cubes, the third level must have 1 + 2 + 3 = 6 cubes, and so on. Thus, the i-th level of the pyramid must have 1 + 2 + ... + (i - 1) + i cubes.

Vanya wants to know what is the maximum height of the pyramid that he can make using the given cubes.

Input

The first line contains integer n (1 ≤ n ≤ 104) — the number of cubes given to Vanya.

Output

Print the maximum possible height of the pyramid in the single line.

Examples
input
Copy
`1`
output
Copy
`1`
input
Copy
`25`
output
Copy
`4`
Note

Illustration to the second sample:

Code Examples

#1 Code Example with C++ Programming

```Code - C++ Programming```

``````#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define endl '\n'
#define debug(n) cout<<(n)<<endl;
const ll INF = 2e18 + 99;

int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);

int n;
cin>>n;

int count = 0;
int pre = 0;
int i = 1;
while(n >= pre + i){
count++;
n -= pre + i;
pre = pre + i;
i++;
}
cout<<count<<endl;
}``````
Copy The Code &

Input

cmd
1

Output

cmd
1