wqewr

int n,s=0,c,f=0,d,s1=0;
    cin>>n;
    while(s>9)
    {
        s=0;
        while(n!=0)
        {
            s=s+n%10;
            n=n/10;
        }
        n=s;
    }
    cout<<s;
    return 0;