#include <stdio.h>

void main(void){
	//調べる数字は0～9の間の数字。
	int turn = 0;
	int input = scanf("%d\n",&turn);
	int targetNumber = 0;
	int pickUp[4];
	int numericList[10] = {0};
	
	for(int i = 0 ; i < turn ; i++ ){
		for(int j = 0 ; j < 4 ; j++ ){
			input = scanf("%d",&pickUp[j]);
		}
		char judge[10] = "a";
		input = scanf("%s",judge);
		if(strcmp(judge,"YES") != 0){
			continue;
		}
		for(int j = 0 ; j < 4 ; j++ ){
			numericList[pickUp[j]]++;
		}
	}
	for(int i = 0 ; i < 10 ; i++){
		if(numericList[i] == 2){
			printf("%d\n",i);
			break;
		}
	}
}