#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")
using namespace std;

void solve(int cs) {
  
  int64_t n;
  cin >> n;
  for (int i = 1; i <= 10; i++) {
    int64_t t = n * i;
    if (n % 10 == 0) {
      cout << i << "\n";
      return;
    }
  }
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int tc = 1;
  // cin >> tc;
  for (int cs = 1; cs <= tc; cs++) {
    solve(cs);
  }
  return 0;
}