package chelper;

import java.math.BigInteger;

import io.InputReader;
import io.OutputWriter;

public class TaskB {
  public void solve(int testNumber, InputReader in, OutputWriter out) {
    String s = in.nextString();

    long n = Long.parseLong(s.substring(0, s.length() - 1)) - 1;
    int p = s.charAt(s.length() - 1);

    BigInteger ans = BigInteger.valueOf(n / 4).multiply(BigInteger.valueOf(16));

    long c = 0;

    switch (p) {
      case 'a': c += 4; break;
      case 'b': c += 5; break;
      case 'c': c += 6; break;
      case 'd': c += 3; break;
      case 'e': c += 2; break;
      case 'f': c += 1; break;
    }

    if ((n % 4) % 2 == 1) {
      c += 7;
    }

    ans = ans.add(BigInteger.valueOf(c));

    out.println(ans);
  }
}