#include <bits/stdc++.h>
#define qio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define debug(x) cerr<<#x<<" "<<x<<endl
#define ll long long 
#define st first
#define nd second
using namespace std;

int n, t, a, sum, res, res1;
int main()
{
	qio;
	cin >> a;
	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;
	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	while (a > 0) {
		res += a % 10;
		a /= 10;
	}
	a = res;
	res = 0;

	cout << a;





}
