Bucks in the Bank

Papa Carlo gave Buratino 1 dollar on his first birthday, which Buratino wisely deposited in the bank. Each following year, Papa Carlo doubled the amount he gave the previous year and added a number of dollars equal to Buratino's age. Buratino continued to deposit all the money in the bank. On which birthday, denoted as N, will the total amount in the bank reach at least S dollars?

Input

A single number, S, where 1 ≤ S ≤ 2^40.

Output

The required value of N.

Examples