#include <bits/stdc++.h>
using namespace std;
 
const int MAXN = 500050;
 
char s[MAXN];
int ans, l, r, n, a[MAXN];
 
inline bool chk(int x)
{
	int len = n, sum = 0;
	for( int i = 1 ; i <= n ; i++ ) a[ i ] = ( s[ i ] - '0' ) * 9;
	a[ 1 ] += 9 * x;
	for( int i = 1 ; i <= len ; i++ )
		if( a[ i ] > 9 )
		{
			if( i == len ) a[ ++len ] = 0;
			a[ i + 1 ] += a[ i ] / 10;
			a[ i ] %= 10;
		}
	for( int i = 1 ; i <= len ; i++ ) sum += a[ i ];
	return sum <= 9 * x;
}
 
int main()
{
#ifdef wxh010910
	freopen( "data.in", "r", stdin );
#endif
	scanf( "%s", s + 1 );
	l = 1, r = n = strlen( s + 1 );
	reverse( s + 1, s + n + 1 );
	while( l <= r )
	{
		int mid = l + r >> 1;
		if( chk( mid ) ) ans = mid, r = mid - 1;
		else l = mid + 1;
	}
	cout << ans << endl;
}
