#include <stdio.h>

 #include <string.h>

 #include <iostream>

 #include <algorithm>

 #include <vector>

 #include <queue>

 #include <set>

 #include <map>

 #include <string>

 #include <math.h>

 #include <stdlib.h>

 #include <time.h>

 #include<string>

 using namespace std;

 class TaroFillingAStringDiv2 {

     public:

     int getNumber(string S) {

     int s1,s2;

     s1=s2=;

     string s=S;

     if(S[]=='?') s[]='A';

     for (int i=;i<s.size();i++)

     {

         if (s[i]=='?') s[i]= s[i-]=='A'?'B':'A';

         if (s[i]==s[i-]) s1++;

     }

     s=S;

     if(S[]=='?') s[]='B';

     for (int i=;i<s.size();i++)

     {

         if (s[i]=='?') s[i]= s[i-]=='A'?'B':'A';

         if (s[i]==s[i-]) s2++;

     }

     return min(s1,s2);

    }

 };