This morning Tolik has understood that while he was sleeping he had invented an incredible problem which will be a perfect fit for Codeforces! But, as a "Discuss tasks" project hasn't been born yet (in English, well), he decides to test a problem and asks his uncle.

After a long time thinking, Tolik's uncle hasn't any ideas on how to solve it. But, he doesn't want to tell Tolik about his inability to solve it, so he hasn't found anything better than asking you how to solve this task.

In this task you are given a cell field n ⋅ m, consisting of n rows and m columns, where point's coordinates (x, y) mean it is situated in the x-th row and y-th column, considering numeration from one (1 ≤ x ≤ n, 1 ≤ y ≤ m). Initially, you stand in the cell (1, 1). Every move you can jump from cell (x, y), which you stand in, by any non-zero vector (dx, dy), thus you will stand in the (x+dx, y+dy) cell. Obviously, you can't leave the field, but also there is one more important condition — you're not allowed to use one vector twice. Your task is to visit each cell of the field exactly once (the initial cell is considered as already visited).

Tolik's uncle is a very respectful person. Help him to solve this task!

Input

The first and only line contains two positive integers n, m (1 ≤ n ⋅ m ≤ 10^{6}) — the number of rows and columns of the field respectively.

Output

Print "-1" (without quotes) if it is impossible to visit every cell exactly once.

Else print n ⋅ m pairs of integers, i-th from them should contain two integers x_i, y_i (1 ≤ x_i ≤ n, 1 ≤ y_i ≤ m) — cells of the field in order of visiting, so that all of them are distinct and vectors of jumps between them are distinct too.

Notice that the first cell should have (1, 1) coordinates, according to the statement.

Examples

Input


2 3


Output


1 1
1 3
1 2
2 2
2 3
2 1

Input


1 1


Output


1 1

Note

The vectors from the first example in the order of making jumps are (0, 2), (0, -1), (1, 0), (0, 1), (0, -2).

import java.util.*;
import java.io.*;
import java.math.BigInteger; 
public class Mamo {
    static long mod=1000000007;
    static Reader in=new Reader();
    static List<Integer >G[];
    static long a[],p[],xp[],xv[];
    static StringBuilder Sd=new StringBuilder(),Sl=new StringBuilder();
    public static void main(String [] args) {
    	//Dir by MohammedElkady
     int n=in.nextInt(),m=in.nextInt();
        	for(int i=0;i<=n;i++) {
        		if(n>i*2)
        		for(int u=1,j=m;u<=m;u++,j--) {
        			if(n-i-i-1==0&&j<u)break;
        			out.append((i+1)+" "+(u)+"\n");
        			if(n-i-i-1==0&&j<=u)break;
        			out.append((n-i)+" "+(j)+"\n");
        		}
        	}
        
    	out.close();
    }
    
    static long ans=0L;
    static boolean v[];
    static ArrayList<Integer>res;
    static  Queue <Integer> pop;
    static  Stack <Integer>rem;
    public static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
    static long gcd(long g,long x){if(x<1)return g;else return gcd(x,g%x);}  
    static class Reader 
    { 
        private InputStream mIs;private byte[] buf = new byte[1024];private int curChar,numChars;public Reader() { this(System.in); }public Reader(InputStream is) { mIs = is;} 
        public int read() {if (numChars == -1) throw new InputMismatchException();if (curChar >= numChars) {curChar = 0;try { numChars = mIs.read(buf);} catch (IOException e) { throw new InputMismatchException();}if (numChars <= 0) return -1; }return buf[curChar++];} 
        public String nextLine(){int c = read();while (isSpaceChar(c)) c = read();StringBuilder res = new StringBuilder();do {res.appendCodePoint(c);c = read();}while (!isEndOfLine(c));return res.toString() ;} 
        public String s(){int c = read();while (isSpaceChar(c)) c = read();StringBuilder res = new StringBuilder();do {res.appendCodePoint(c);c = read();}while (!isSpaceChar(c));return res.toString();} 
        public long l(){int c = read();while (isSpaceChar(c)) c = read();int sgn = 1;if (c == '-') { sgn = -1 ; c = read() ; }long res = 0; do{ if (c < '0' || c > '9') throw new InputMismatchException();res *= 10 ; res += c - '0' ; c = read();}while(!isSpaceChar(c));return res * sgn;} 
        public int nextInt(){int c = read() ;while (isSpaceChar(c)) c = read();int sgn = 1;if (c == '-') { sgn = -1 ; c = read() ; }int res = 0;do{if (c < '0' || c > '9') throw new InputMismatchException();res *= 10 ; res += c - '0' ; c = read() ;}while(!isSpaceChar(c));return res * sgn;} 
        public double d() throws IOException {return Double.parseDouble(s()) ;}
        public boolean isSpaceChar(int c) { return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; } 
        public boolean isEndOfLine(int c) { return c == '\n' || c == '\r' || c == -1; } 
        public int[] arr(int n){int[] ret = new int[n];for (int i = 0; i < n; i++) {ret[i] = nextInt();}return ret;}
    }
}

class stree{
	public stree(int n,long a[]) {
		this.a=a;
		seg=new long[n*4];
		lazy=new long[n*4];
		build(1,0,n-1);
	}
	long seg[], a[],lazy[];
	    void check(int p,int s,int e) {
	        if(lazy[p]!=0) {
	            seg[p] += lazy[p];
	            if(s!=e) {
	                lazy[2*p] += lazy[p];
	                lazy[2*p+1] += lazy[p];
	            }
	            lazy[p] = 0;
	        }
	    }
	    
	     void build(int p,int s,int e) {
	        check(p,s,e);
	        
	        if(s==e) {
	            seg[p] = a[s];
	            return;
	        }
	        
	        build(2*p,s,(s+e)/2);
	        build(2*p+1,(s+e)/2+1,e);
	        
	        seg[p] = Math.max(seg[2*p], seg[2*p+1]);
	    }
	    
	   void update(int p,int s,int e,int i,int v) {
	        check(p,s,e);
	        
	        if(s==e) {
	            seg[p] = v;
	            return;
	        }
	        
	        if(i<=(s+e)/2) update(2*p,s,(s+e)/2,i,v);
	        else update(2*p+1,(s+e)/2+1,e,i,v);
	        
	        seg[p] = Math.max(seg[2*p],seg[2*p+1]);
	    }
	    
	     void update(int p,int s,int e,int a,int b,int v) {
	        check(p,s,e);
	        
	        if(s>=a && e<=b) {
	            seg[p] += v;
	            
	            if(s!=e) {
	                lazy[2*p] += v;
	                lazy[2*p+1] += v;
	            }
	            
	            return;
	        }
	        
	        if(s>b || e<a)
	            return;
	        
	        update(2*p,s,(s+e)/2,a,b,v);
	        update(2*p+1,(s+e)/2+1,e,a,b,v);
	        
	        seg[p] = Math.max(seg[2*p],seg[2*p+1]);
	    }
    
 
    
    long get(int p,int s,int e,int a,int b) {
        if(s>=a && e<=b)
            return seg[p];
        
        if(s>b || e<a)
            return Long.MIN_VALUE; 
        
        return Math.max(get(2*p,s,(s+e)/2,a,b), get(2*p+1,(s+e)/2+1,e,a,b));
    }
}
class node implements Comparable<node>{
int a, b;
node(int tt,int ll){
a=tt;b=ll;
}
    @Override
    public int compareTo(node o) {
    return b-o.b;    
    }
}
class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                     InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
}
 
class Sorting{
 
 public static long[] bucketSort(long[] array, int bucketCount) {
 
 if (bucketCount <= 0) throw new IllegalArgumentException("Invalid bucket count");
 
 if (array.length <= 1) return array; //trivially sorted
 
 
 
 long high = array[0];
 
 long low = array[0];
 
 for (int i = 1; i < array.length; i++) { //find the range of input elements
 
 if (array[i] > high) high = array[i];
 
 if (array[i] < low) low = array[i];
 
 }
 
 double interval = ((double)(high - low + 1))/bucketCount; //range of one bucket
 
 
 ArrayList<Long> buckets[] = new ArrayList[bucketCount];
 
 for (int i = 0; i < bucketCount; i++) { //initialize buckets
 
 buckets[i] = new ArrayList();
 
 }
 
 
 
 for (int i = 0; i < array.length; i++) { //partition the input array
 
 buckets[(int)((array[i] - low)/interval)].add(array[i]);
 
 }
 
 
 int pointer = 0;
 
 for (int i = 0; i < buckets.length; i++) {
 
 Collections.sort(buckets[i]); //mergeSort
 
 for (int j = 0; j < buckets[i].size(); j++) { //merge the buckets
 
 array[pointer] = buckets[i].get(j);
 
 pointer++;
 
 }
 
}
 
return array;
 
}
}