#include <iostream>
using namespace std;
int main()
{
    int n;
    cin>>n;
    string s;
    int a=1;
    int counter=0;
    for(int i=0; i<n; i++)
    {
        cin>>s;
        if((s[0]=='A' || s[0]=='P' || s[0]=='R' || s[0]=='O' ) && a==2) { a=1; counter++;}
        else
        if((s[0]=='A' || s[0]=='P' || s[0]=='R' || s[0]=='O' ) && a==3) { a=1; counter+=2;}
        else
        if((s[0]=='B' || s[0]=='M' || s[0]=='S') && a==1){ a=2; counter++;}
        else
        if((s[0]=='B' || s[0]=='M' || s[0]=='S') && a==3){ a=2; counter++;}
        else
        if((s[0]=='D' || s[0]=='G' || s[0]=='J' || s[0]=='K' || s[0]=='T' || s[0]=='W' ) && a==1) { a=3; counter+=2;}
        else
        if((s[0]=='D' || s[0]=='G' || s[0]=='J' || s[0]=='K' || s[0]=='T' || s[0]=='W' ) && a==2) { a=3; counter++;}

    }
    cout<<counter;
    system("pause");
    return 0;
}