#include <iostream>
#include <cstring>
using namespace std;
char s1[101], s2[101];
int main() {
cin.getline(s1, 101);
cin.getline(s2, 101);
int lungime1 = strlen(s1);
int lungime2 = strlen(s2);
for (int i = 0; i < lungime1; ++i){
if (s1[i] == s2[0]){
int j = 1;
++i;
while (s1[i] == s2[0] && j < lungime2){
++i; ++j;
}
if (j == lungime2){
cout << "DA";
return 0;
}
}
}
cout << "NU";
}
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