#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<assert.h>
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
 
int main(){
  int i, j;
  int R, C;
  int in[200][200];
  int mn[200], mx[200];
  int res;
 
  assert( scanf("%d%d",&R,&C)==2 );
  assert(1<=R&&R<=100 && 1<=C&&C<=100);
 
  rep(i,R) rep(j,C) assert( scanf("%d",in[i]+j)==1 ), assert(1 <= in[i][j] && in[i][j] < 100000000);
 
  rep(i,R) mn[i] = in[i][0];
  rep(i,C) mx[i] = in[0][i];
  rep(i,R) rep(j,C){
    if(mn[i] > in[i][j]) mn[i] = in[i][j];
    if(mx[j] < in[i][j]) mx[j] = in[i][j];
  }
 
  res = 0;
  rep(i,R) rep(j,C) if(in[i][j] == mn[i] && in[i][j] == mx[j]) res = in[i][j];
 
  if(res) printf("%d\n",res); else puts("GUESS");
 
  return 0;
}