#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>


/*
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::::::::::::::::::::::::::::::::::::::::''`_,-''.,...  `::::::::::::::::::
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::::::::::'' ,;!!!;,`::::::::::' .-`.,,,zcccc,,cccd$$"",;> `::::::::::::::
:::::::::' ;!!!!!!!!; ``:::::' ;' ,c$$$$$$$$$$$CC<<"  ````_ ::::::::::::::
:::::::' ;!!!!!!!!!!!!!;   ' ;! z$$$$$$$$$$$$$$$$$$$$$$??". ::::::::::::::
::::::: <!!!!!!!!!!!!!' .  .!',c$$$$$$$$$$$$$c, `"""',;;<!! ::::::::::::::
:::::: ,!!!!!!!!!!!'`,;! .<! ,$$$$$$$$$$$$$$$$hc,,,..- !!!! `:::::::::::::
::::'  <!!!!!!!!!' .<!!!;!! ,$$$$$""???$$$"""?????"" .<!!!! ::::::::::::::
::: ;><!!!!!!!!! ,<!!!!!!!',c,  "??.< . "??h. -;;;;!!!!!!!' ::::::::::::::
::: !!!!!!!!!!' ;!!!!!!!!' d$$h.`$ccr,$h `;,."  `!!!!!!!!! :::::::::::::::
:::.`<!!!!!!!' !!!!!!!!!! dP"""?.`$$F`$$h.`!!!!!!!!!!!!!! .:::::::::::::::
::::. <!!!!!! !!!!!!!!!! ,$ .nn.' "$$ P"   <!!!!!!!!!!!' .::::::::::::::::
:::::. <!!!! ;!!!!!!!!!! $$ MMMMx  ?$  ,dx `!!!!!!!!!!' ::::::::::::::::::
```:::: `!!! !!!'!!!!!!  `$ MMMMMM, $r MMMr !!!!!!!!' .:::::::::::::::::::
`!!;,.`' ``' ``,;!!!!' ch." 4MMMMMM "$ 4MMM `!!!!!' ..::::::::::::::::::::
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MMn.`"?hc,d$$$$$$$$$$$$$$$$$$. `P    $P'   -??P== `:::::::::::::::::::::::
MMMMMnx`"?$$$$$$$$$$$P".,.`"??$ccccc$.z$$$$.  `' .:::::::::::::::::'    ''
MMMMMM,' .?$$$$$$$$$$ d$$$    d$$$$$$$$$$$$$h..``::::::::::::::::'
MMMMMMMn `?$$$$$$$$$$,.?$$h. =."?$$$$$$$$$$$$$$hc,.``'::::::::::'
MMMMMMMM ;, `"??$$$$$$h  ?$$h. -m,``""??$$$$$$$$$$$$$c,.``````'
MMMMMMM> !!! ?cc,.,d$$$$h.`"?$hc   `P  .`"?$$$$$$$$$$$$$$$$$$$          .:
MMMMMMM ,!!'. $$$$$$$$$??=== `"""=c, " P  n. "$$$$$$$$$$$$$$$$c_    ,.::::
MMMMMMP !!! Mr<$$$$"".,c,;M ;<!! ..""=_ ' 4 .br .`""??$$$$$$$$??"".:::::::
MMMMMM';!!',M>'$$$$$$$$$>4M `!!! 4MMbn.`"=cc," -'P",c=.,.`.. .=  :::::::::
MMMMM' !!! dMb $$$$$$$$P MM> !!! 4MMMMMMr :..`"-._""Pr4"'-P" .,.`:::::::::
MMMM' <!!!,MMM "$$$$$$P dMM>;!!! 4MMMMMMb :::::.. "-=cczyycc??" .:::::::::
MMMP <!!! dMMMb "?$$P" uMMM>;!!! 4MMMMMMMr`:::::::::.........:::::::::::::
MMP';!!! ;MMMMMMn,.".uMMMMM ;!!! MMMMMMMMM,`::::::::::::::::::::::::::::::
MM ;!!!! MMMMMMMMMMMMMMMMMM !!!! MMMMMMMMMb `:::::::::::::::::::::::::::::
M" !!!! uMMMMMMMMMMMMMMMMMP !!! ;MMMMMMMMMMx :::::::::::::::::::::::::::::
P.!!!! ,MMMMMMMMMMMMMMMMMM ,!!! MMMMMMMMMMMMx`::::::::::::::::::::::::::::
 !!!!> MMMMMMMMMMMMMMMMMMP !!!',MMMMMMMMMMMMM `:::::::::::::::::::::::::::
*/


int main() {
	long long n;

	std::cin >> n;

	long long ans = 10000000000000000;
	for (long long i = 1; i * i <= n; i++)
	{
		if (std::ceil(1.0 * n / i) == std::floor(1.0 * n / i)) {
			ans = std::min(ans, static_cast<long long>(std::max(std::log10(i), std::log10(n / i)) + 1));
		}
	}

	std::cout << ans << std::endl;

	return 0;
}

Measured memory_bytes: 256