description: Monocarp is playing a computer game. Now he wants to complete the first level of this game.
  
  A level is a rectangular grid of 2 rows and n columns. Monocarp controls a character, which starts in cell (1, 1) — at the intersection of the 1-st row and the 1-st column.
  
  Monocarp's character can move from one cell to another in one step if the cells are adjacent by side and/or corner. Formally, it is possible to move from cell (x_1, y_1) to cell (x_2, y_2) in one step if |x_1 - x_2| ≤ 1 and |y_1 - y_2| ≤ 1. Obviously, it is prohibited to go outside the grid.
  
  There are traps in some cells. If Monocarp's character finds himself in such a cell, he dies, and the game ends.
  
  To complete a level, Monocarp's character should reach cell (2, n) — at the intersection of row 2 and column n.
  
  Help Monocarp determine if it is possible to complete the level.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 100) — the number of test cases. Then the test cases follow. Each test case consists of three lines.
  
  The first line contains a single integer n (3 ≤ n ≤ 100) — the number of columns.
  
  The next two lines describe the level. The i-th of these lines describes the i-th line of the level — the line consists of the characters '0' and '1'. The character '0' corresponds to a safe cell, the character '1' corresponds to a trap cell.
  
  Additional constraint on the input: cells (1, 1) and (2, n) are safe.
  
  Output
  
  For each test case, output YES if it is possible to complete the level, and NO otherwise.
  
  Example
  
  Input
  
  
  4
  3
  000
  000
  4
  0011
  1100
  4
  0111
  1110
  6
  010101
  101010
  
  
  Output
  
  
  YES
  YES
  NO
  YES
  
  Note
  
  Consider the example from the statement.
  
  In the first test case, one of the possible paths is (1, 1) → (2, 2) → (2, 3).
  
  In the second test case, one of the possible paths is (1, 1) → (1, 2) → (2, 3) → (2, 4).
  
  In the fourth test case, one of the possible paths is (1, 1) → (2, 2) → (1, 3) → (2, 4) → (1, 5) → (2, 6).
solution: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.*;
  
  public class Main {
      public static void main(String[] args) throws Exception {
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          
          StringTokenizer st = new StringTokenizer(br.readLine());
          int t = Integer.parseInt(st.nextToken());
          
          StringBuilder sb = new StringBuilder();
  
          while (t != 0) {
              st = new StringTokenizer(br.readLine());
              int n = Integer.parseInt(st.nextToken());
              
              char[][] ar=new char[2][n];
              for(int i=0;i<2;i++){
                  ar[i]=br.readLine().toCharArray();
              }
              
              boolean early=false;
              for(int j=0;j<n;j++){
                  if(ar[0][j]=='1' && ar[1][j]=='1'){
                      early=true;
                      break;
                  }
              }
              if(early){
                  sb.append("NO\n");
              }
              else{
                  sb.append("YES\n");
              }
              t--;
          }
          System.out.println(sb);
      }
      
      public static void swap(int[] ar,int i,int j){
          int temp=ar[i];
          ar[i]=ar[j];
          ar[j]=temp;
      }
      
      public static class Pair{
          int x;
          int y;
          
          Pair(int x,int y){
              this.x=x;
              this.y=y;
          }
          
          public int getX(){
              return x;
          }
          
          public int getY(){
              return y;
          }
      }
  }
  
  