#include <iostream>
#include<cstring>
using namespace std;

int main()
{
    char s1[21],s2[21],aux;
    cout<<"s1=";
    cin>>s1;
    cout<<"s2=";
    cin>>s2;
    int i,j;
    if(strlen(s1)!=strlen(s2))
        cout<<"nu";
    else
    {
        for(i=0;i<strlen(s1)-1;i++)
            for(j=i+1;j<strlen(s1);j++)
                if(s1[i]>s1[j])
                {
                    aux=s1[i];
                    s1[i]=s1[j];
                    s1[j]=aux;
                }
        for(i=0;i<strlen(s2)-1;i++)
            for(j=i+1;j<strlen(s2);j++)
                if(s2[i]>s2[j])
            {
                aux=s2[i];
                s2[i]=s2[j];
                s2[j]=aux;
            }
        if(strcmp(s1,s2)==0)
            cout<<"da";
        else
        cout<<"nu";
    }
    return 0;
}