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

#define READ_BUFSIZE ( 16 )
#define READ_DELIMITER ( " " )


//標準入力取得（１行）

int GetStdin( char* pszStr, int lMaxLen )
{
	int lLen = 0;

    memset( pszStr, 0, lMaxLen );
    if( fgets( pszStr, lMaxLen, stdin ) )
    {
	    lLen = strlen( pszStr );
	    if( lLen >= 1 )
	    {
			if( pszStr[ lLen - 1 ] == 0x0A )
			{
				pszStr[ lLen - 1 ] = 0;
				lLen--;
			}
		}
	}
	
	return( lLen );
}

//標準入力を取得
//区切り文字で区切られている文字列を取り出す
//取り出した文字列のポインタをポインタ配列にセットする  (文字列型)
int split(char *pszStr, int lStrMax, const char *pszDelim, char *apszOutList[]) {
    char *pszToken;
    int count = 0;
    char *pszNext_token = 0;
	int lLen = 0;
	int lNum = 0;

    memset( pszStr, 0, lStrMax );
    lLen = GetStdin( pszStr, lStrMax );
    
	if( lLen > 0 )
	{

	    pszToken = strtok( pszStr, pszDelim );

	    while ( pszToken != NULL ) 
	    {
            apszOutList[ lNum ] = pszToken;
			lNum++;
//	        pszToken = strtok_s(NULL, pszDelim, &pszNext_token);
		    pszToken = strtok( NULL, pszDelim );
	    }
	}
    return lNum;
}


int main(int argc, char *argv[]) 
{
	char szRead[READ_BUFSIZE] = "";
	char* psOutbuf[5] = { 0 };

	split( szRead, READ_BUFSIZE, READ_DELIMITER, psOutbuf );

	int N = atoi( psOutbuf[0] );

	char map['9'+1] = {0};

	for( int i = 0; i < N; i++ )
	{
		split( szRead, READ_BUFSIZE, READ_DELIMITER, psOutbuf );

		if( strcmp( psOutbuf[4], "YES" ) == 0 )
		{
			for( int j = '0'; j <= '9'; j++ )
			{
				int k = 0;
				bool bFlag = false;
				for( k = 0; k < 4; k++ )
				{
					if( j == *psOutbuf[k] )
					{
						bFlag = true;
						break;
					}

				}

				if( bFlag && map[j] != -1 )
					map[j] = 1;
				else
					map[j] = -1;

			}
		}
		else
		{
			map[ *psOutbuf[0] ] = -1;
			map[ *psOutbuf[1] ] = -1;
			map[ *psOutbuf[2] ] = -1;
			map[ *psOutbuf[3] ] = -1;
		}
	}
	
	int l = '0';
	for( l = '0'; l <= '9'; l++ )
	{
		if( map[l] == 1 )
		{
			printf( "%c\n", l );
			break;
		}

	}

	if( l > '9' )
	{
		for( l = '0'; l <= '9'; l++ )
		{
			if( map[l] == 0 )
			{
				printf( "%c\n", l );
				break;
			}

		}
	}

	return 0;

}