53. 2292(벌집)

let input = require('fs').readFileSync('/dev/stdin').toString().split();

const N = parseInt(input)

let cnt = 1
let i = 1

if(N===1){
    console.log(1);
}

else {
    while(true){
        if(N <= cnt){
            console.log(i);
            break;
        }
        else{
            cnt += (i * 6);
            i++;
        }
    }
}