#include<iostream>
int main()
{
int def;
int one, ten;
int tmp=0;
std::cin >> def;
if (def == 0)
{
std::cout << 1;
return 0;
}
int count=0;
if (def < 10)
def *= 10;
while (def!=tmp) {
if (count == 0)
tmp = def;
one = tmp % 10;
tmp = tmp / 10;
ten = tmp % 10;
tmp = one + ten;
tmp = tmp % 10;
tmp = one * 10 + tmp;
count++;
}
std::cout << count;
}