#include <bits/stdc++.h>
using namespace std;



int main(){
    unsigned long long n;
    string str;
    char pl;
    cin>>str;
    pl=str[str.length()-1];
    str.resize (str.size () - 1);
    stringstream(str) >> n;
    unsigned long long ans=0;
    if((n-1)%4==0 || (n-1)%4==2)
        ans=((n-1)/4)*4+((n-1)/4)*12;
    else
        ans=((n-1)/4)*4+1+((n-1)/4)*12+ 6;

    if(pl=='a')     ans+=4;
    else if(pl=='b')    ans+=5;
    else if(pl=='c')   ans+=6;
    else if(pl=='d')   ans+=3;
    else if(pl=='e')   ans+=2;
    else    ans+=1;
    cout<<ans;
    return 0;
}