BAI2 HSGHN L12 V1 2019-2020

#define task "BAI2"

#include <iostream>
#include <cstdio>
#include <cmath>

using namespace std;

using ll = long long;

int a, b, k;

void Read()
{
    cin >> a >> b >> k;
}

void Solve()
{
    if (k == 10)
        cout << 1;
    else
    {
        ll tmp = 10;
        for (int i = 1;; ++i, tmp *= 10)
        {
            if ((a * tmp * 10 + b) % (k - 10) == 0)
                if ((int)log10((a * tmp * 10 + b) / (k - 10)) + 1 == i)
                {
                    cout << (a * tmp * 10 + b) / (k - 10);
                    return;
                }
        }
    }
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}