180425_1568_새

	//https://www.acmicpc.net/problem/1568 #include <iostream>
	using namespace std;
	int main(){
	int n;
	cin >>n;
	int ans=0;
	while(1){
	for(int i=1; n>=i ; i++){
	n-=i;
	++ans;
	}
	if(n==0) break;
	}
	cout << ans <<endl;
	return 0;
	}