email

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

int is_email_address( char *p )
{
    int i,
        pont = 0,
        h1 = strlen(p),
        kukac = -1;

    for (i = 0; i < h1; i++)
    {
        if ( !isalnum(p[i]) && p[i] != '-' && p[i] != '.' && p[i] != '@')
            return 0;

        if (p[i] == '@')
            {
                if(kukac == -1)
                    kukac = i;
                else
                    return 0;

                if(i == 0 || i == h1-1)
                    return 0;
            }
    }

    if(kukac == -1)
        return 0;

    for (i = kukac + 1; i < h1; i++)
    {
        if (p[i] == '.')
        {
            pont++;
            if(p[i-1] == '.' || p[i-1] == '@')
                return 0;
            if(h1 - i <= 2)
                return 0;
        }
    }

    if (pont < 1)
        return 0;

    return 1;
}

#include <stdio.h>
#include <stdlib.h>
int main()
{
  char line[ 50 ];
  int is_email_address( char * );
  while ( gets( line ) != NULL )
    if ( is_email_address( line ) )
      puts( "YES" );
    else
      puts( "NO" );
  return EXIT_SUCCESS;
}