#include <iostream>
#include <set>
using namespace std;
int main(){
  string s;cin>>s;
  pair<int,int> nw = {0,0};
  set<pair<int,int>> A;
  A.insert(nw);
  for(int i = 0; s.size() > i; i++){
    if(i%2){
      if(s[i] == 'a')nw.second--;
      else if(s[i] == 'b')nw.first++;
      else nw.second++;
    }else{
      if(s[i] == 'a')nw.second++;
      else if(s[i] == 'b')nw.first--;
      else nw.second--;
    }
    A.insert(nw);
  }
  cout << A.size() << endl;
}