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.IOException;
  import java.io.InputStreamReader;
  import java.util.*;
  
  	public class practice{
  		public static void main(String[] args){
  			FastScanner r = new FastScanner();					
  			int t = r.i() ,n;
  			char[] a,b;
  			StringBuffer ans = new StringBuffer("");
  			while(t-->0) {
  				n = r.i();
  				a =r.n().toCharArray();
  				b =r.n().toCharArray();
  				
  				if(a[0] =='1') {
  					ans.append("NO\n");
  					continue;
  				}
  				boolean f = true;
  				
  				for(int i=1;i<n;i++) {
  					if(a[i] =='1' && b[i]=='1') {
  						f = false;
  						break;
  					}
  						
  				}
  				ans.append(f ? "YES\n" : "NO\n");
  				
  			}				
  			p(ans);
  		}
  
  		
  		static <T> void p(T s) {
  			System.out.println(s);
  		}
  		
  		static void p() {
  			System.out.println();
  		}		
  		static <T> void pn(T s) {
  			System.out.print(s);
  		}
  
  	}
  		
  
  	
  	class FastScanner {
  	    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
  	    StringTokenizer st=new StringTokenizer("");
  	    String n() {
  	        while (!st.hasMoreTokens())
  	            try {
  	                st=new StringTokenizer(br.readLine());
  	            } catch (IOException e) {
  	                e.printStackTrace();
  	            }
  	        return st.nextToken();
  	    }
  	    int[] ia(int n) {
  	    	int[] arr = new int[n];
  	    	for(int i=0;i<n;i++)
  	    		arr[i] = i();
  	    	return arr;
  	    }
  	    String[] sa(int n) {
  	    	String[] arr = new String[n];
  	    	for(int i=0;i<n;i++)
  	    		arr[i] = n();
  	    	return arr;
  	    }
  	    long[] la(int n) {
  	    	long[] arr = new long[n];
  	    	for(int i=0;i<n;i++)
  	    		arr[i] = l();
  	    	return arr;
  	    }
  	    String nl()
  	    {
  	        String str = "";
  	        try
  	        {
  	            str = br.readLine();
  	        }
  	        catch (IOException e)
  	        {
  	            e.printStackTrace();
  	        }
  	        return str;
  	    }
  
  	    int i() {
  	        return Integer.parseInt(n());
  	    }
  	    long l() {
  	        return Long.parseLong(n());
  	    }
  	}
  