#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll sum(ll n)
{
    ll sum = 0;
    while (n)
    {
        sum += n % 10;
        n /= 10;
    }
    return sum;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll n;
    cin >> n;
    while (n >= 10)
    {
        n = sum(n);
    }
    cout << n << endl;
}
### Prompt

Construct a cpp code solution to the problem outlined:

Many people are aware of DMCA – Digital Millennium Copyright Act. But another recently proposed DMCA – Digital Millennium Calculation Act – is much less known.

In this problem you need to find a root of a number according to this new DMCA law.

Input

The input contains a single integer a (1 ≤ a ≤ 1000000).

Output

Output the result – an integer number.

Examples

Input


1


Output


1


Input


81


Output


9

### Response

```cpp
#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll sum(ll n)
{
    ll sum = 0;
    while (n)
    {
        sum += n % 10;
        n /= 10;
    }
    return sum;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll n;
    cin >> n;
    while (n >= 10)
    {
        n = sum(n);
    }
    cout << n << endl;
}
```