#include <iostream>
using namespace std;
 
int main() {
  // Introduc variabilele a, b, c şi x;
  int a, b, c, x;
  // Citesc a, b, c, x;
  cin >> a >> b >> c >> x;
  if (c != x % 10) cout << "NU";
  if (c == x % 10) { // verificam "c"
    // Introduc variabila “cnt” sa numar cifrele;
    int cnt = 0;
    // parcurg x;
    int x_copy;
    while (x > 0) {
      ++cnt;
      x_copy = x; // identific "b" introducand o variabila copie a lui x 
      //pentru a mentine penultima valoare a lui x
      x /= 10;
    }
    if (b == x_copy) {
    	if (a == cnt) 
     // verificam a si b
      cout << "DA";
    }
  }
  return 0;
}

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