#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define endl '\n'
#define Endl '\n'

using namespace std;

const int N = 2e5 + 5;
int tc, n, m, a[N];

random_device rd;
mt19937 eng(rd());

int getRandomNumberInRange(int min, int max) {
    uniform_int_distribution<> distribution(min, max);
    return distribution(eng);
}

ll getAnswer(ll n) {
    for (ll i = 1; i <= 10; i++) {
        ll cur = i * n;
        if (cur % 10 == 0) {
            return i;
        }
    }
    return 0;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); // cout.tie(0);
    cin >> n;
    cout << getAnswer(n) << endl;

    return 0;
}