// verificarea daca un cuv este sau nu uniform (conditii:-nr lit mici=nr lit mari; -niciun alt caract in sir
#include <iostream>
#include <cstring>
using namespace std;

int main()
{
    char s[21];
    int i,ok=1,k=0,z=0;
    cout<<"s=";
    cin>>s;
    for(i=0;i<strlen(s)-1;i++)
            if(s[i]>=s[i+1])
                ok=0;

    if(ok)
        cout<<"da";
    else
        cout<<"nu";


    return 0;
}