#include<cstdio>
#include<iostream>
#include<cstring>
#include<string>
#include<cmath>
#include<map>
#include<algorithm>
#include<vector>
#include<set>
#define Quick ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define ll long long
#define INF 0x3f3f3f3f
#define PI acos(-1)
#define mem(a, b) memset(a, b, sizeof a)
using namespace std;
const int N = 1e6 + 3;
const int mod =1e9 + 7; 
int a[N];
ll dp[N];
int vis[N];
int tot = 0;

int main()
{
	Quick;
	int n; cin >> n;
	cout << (n - 1) % 9 + 1 << endl;;
}

