Codeforces 492A Vanya and Cubes【水题】

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

1

output

1

input

25

output

4

Note

Illustration to the second sample:

题目大意：

一种搭积木的游戏，第一层有一个，第二层有三个，第三层有六个，第四层有十个、依次类推，问现在手里一共有N个积木，问最多能够撘出来最高的积木层数。

思路：

直接模拟计算即可。

#include
#include
using namespace std;
#define ll __int64
int main()
{
    int n;
    while(~scanf("%d",&n))
    {
        ll sum=1;
        ll now=3;
        ll tmp=3;
        ll output=1;
        for(int i=1;i<=n;i++)
        {
            if(n>=sum)output=i;
            else break;
            sum+=now;
            now+=tmp;
            tmp++;
        }
        printf("%I64d\n",output);
    }
}