492A - Vanya and Cubes

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;
int arr[201], sum[201];

int main() {

    arr[0] = 0;
    for(int i = 1; i < 201; ++i) {
        arr[i] = arr[i-1]+i;
    }
    sum[0] = 0;
    for(int i = 1; i < 201; ++i) {
        sum[i] = sum[i-1] + arr[i];
    }
    int n;
    int id = 0;
    cin >> n;
    while(n >= sum[id]) id++;
    cout << id - 1 << endl;
    return 0;
}