import java.util.*;
public class Kattis {
private static int ball = 1;
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String[] moves = sc.nextLine().split("");
for(String move: moves)
swap(move);
System.out.println(ball);
}
static void swap(String move){
if(ball == 1)
switch (move){
case "A": ball = 2; break;
case "C": ball = 3;
}
else if(ball == 2)
switch (move){
case "A": ball = 1; break;
case "B": ball = 3;
}
else
switch (move){
case "B": ball = 2; break;
case "C": ball = 1;
}
}
}