#include <stdio.h>

int getNum(int n){
	if(n == 1)
		return 1;
	else
		return getNum(n-1) + n - 1;

}


void main()
{
	int s = 0,i = 1;
	
	while(s <= 5000){
		s += getNum(i);
		i++;
	}
	printf("%d",s);
	
}

/**************************************************************
	Problem: 1146
	User: admin
	Language: C
	Result: Accepted
	Time:6 ms
	Memory:1036 kb
****************************************************************/