#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(false);cin.tie(0);
#define ch(a) (int(a-'A'))
#define mm(a) memset(a,0,sizeof(a))
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define inf  0x7FFFFFFF
typedef long long ll;
const int Maxx=1e7+5;
int main()
{
    int n;
    scanf("%d",&n);
    printf("%d\n",(n-1)%9+1);
    return 0;
}