#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;
int main()
{
    char s[100];
    int i,ind=0;
    cin>>s;
    for (i=0;s[i];i++)
    {
        if (s[i]==s[i+1])
        {
            ind=1;
            break;
        }
    }
    if (ind==0)
    cout<<"nu";
    else
    cout<<"da";
    return 0;
}