#include <iostream>

using namespace std;
typedef long long ll;
class Task
{
    public:
       void solve(istream& in,ostream& out)
       {
          string s;
          cin >>s;
          ll n=s.length();
          char seat=s[n-1];
          ll a=atol(s.substr(0,n-1).c_str());
          ll res;

          if (a%4==1)
          {
              ll x=a-1;
              res=(x/4)*12+x+(index(seat));
          }

          else if (a%4==2)
          {
              ll x=a-2;
              res=(x/4)*12+x+(index(seat));
              res+=7;
          }

          else if (a%4==3)
          {
              a=a-2;
              ll x=a-1;
              res=(x/4)*12+x+(index(seat));
          }

          else if (a%4==0)
          {
              a-=2;
              ll x=a-2;
              res=(x/4)*12+x+(index(seat));
              res+=7;
          }

          cout <<res<<endl;
       }

       ll index(char a)
       {
          if (a=='f')
          {
             return 1;
          }
          else if (a=='e')
          {
             return 2;
          }
          else if (a=='d')
          {
             return 3;
          }
          else if (a=='a')
          {
             return 4;
          }
          else if (a=='b')
          {
             return 5;
          }
          else
          {
             return 6;
          }
       }

};
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    istream& in(cin);
    ostream& out(cout);
    Task solver;
    solver.solve(in,out);
    return 0;
}