文本

#include <bits/stdc++.h>
using namespace std;
const int N = 114514;
int sum,sum2;
int main()
{
    int m;
    int n;
    cin>>n;
    for(m=1;m<=N;m++)
    {
        sum = (1+m)*m/2;
        sum2 = sum*sum;
        if(sum2>n)
        {
            break;
        }
    }
    cout<<m-1;

}