#include<iostream>
#include<string>
using namespace std;
int main()
{
    int n,k=0;
    char t,s;
    cin>>n;
    string a[1001];
    for(int i=0;i<n;i++)
        cin>>a[i];
    for(int i=0;i<n-1;i++)
    {
        t=a[i][0];
        s=a[i+1][0];

        if((t=='A' || t=='P' || t=='O' || t=='R') &&
           (s=='A' || s=='P' || s=='O' || s=='R'))
           k+=0;
        if((t=='A' || t=='P' || t=='O' || t=='R') &&
           (s=='B' || s=='M' || s=='S'))
           k+=1;
        if((t=='A' || t=='P' || t=='O' || t=='R') &&
           (s=='D' || s=='G' || s=='J' || s=='K' || s=='T' || s=='W'))
           k+=2;

        if((t=='B' || t=='M' || t=='S') &&
           (s=='B' || s=='M' || s=='S'))
           k+=0;
        if((t=='B' || t=='M' || t=='S') &&
           (s=='A' || s=='P' || s=='O' || s=='R'||
            s=='D' || s=='G' || s=='J' || s=='K' || s=='T' || s=='W'))
           k+=1;

        if((t=='D' || t=='G' || t=='J' || t=='K' || t=='T' || t=='W') &&
           (s=='D' || s=='G' || s=='J' || s=='K' || s=='T' || s=='W'))
           k+=0;
        if((t=='D' || t=='G' || t=='J' || t=='K' || t=='T' || t=='W') &&
           (s=='B' || s=='M' || s=='S'))
           k+=1;
        if((t=='D' || t=='G' || t=='J' || t=='K' || t=='T' || t=='W') &&
           (s=='A' || s=='P' || s=='O' || s=='R'))
           k+=2;
    }

    cout<<k;
    return 0;
}

1
Dumbo --->>> is not working

Right Answer is 2  but your answer 0