#include <iostream>

using namespace std;
int a,b,a1,b1,n,S1,S2;
int main()
{
    cin>>a>>b;
    S1=S2=0;
    a1=a;
    b1=b;
    while(a!=0)
    {
        S1=S1+1;
        a=a/10;
    }
    while(b!=0)
    {
        S2=S2+1;
        b=b/10;
    }
    if(S1!=S2)
    {
        cout<<"NU";
    }
    else
    {
        while(a1!=0 && b1!=0)
        {
            if(a1%10==b1%10)
            {
                n++;
            }
            a1=a1/10;
            b1=b1/10;
        }
        cout <<"DA"<<endl<<n;
    }
    return 0;
}