#include <stdio.h>
#include <iostream.h>
#include <string.h>
struct Ta{
  char SL [ 200 ];
  unsigned len;
  };
int	main()
  {
  Ta a;
  char  b[ 200 ];
  int i,j,l;
  cout << "Enter string:";
  cin >> b;
  l=strlen(b);
  j=0;
  for(i=0;i<l;i++)
    {
    if(b[i]=='(')
      {
      j++;
      };
    if(b[i]==')')
      {
      j--;
      };
    if(j<0)
      {
      break;
      };
    };
  if(j==0)
    {
    cout <<"OK!"<<endl;
    }
    else
    {
    cout <<"Error"<<endl;
    };
  return 0;
  };