collatz.d

import std.stdio, std.conv, std.string;

void main() {
	int N = readln.chomp.to!int;
	N.solve(0).writeln;
}

ulong solve(int n, int c) {
	return n == 1 ? c : solve(n%2?n*3 + 1 : n/2, c+1);
}