#include<bits/stdc++.h>
using namespace std;
int main(){
	int a[4],x;
	string str;
	a[1] = 1;
	cin >> str;
	for(int i = 1;i <= str.size();i++){
		if(str[i]=='A')swap(a[1],a[2]);
		if(str[i]=='B')swap(a[2],a[3]);
		if(str[i]=='C')swap(a[1],a[3]);
	}
	for(int j = 1;j <= 3;j++){
		if(a[j]==1){
			x=j;
			break;
		}
	}
	if(x == 1){
		x=4;
	}
	cout << x-1;
	return 0;
}