#include <bits/stdc++.h>
using namespace std;
long long ans1 = LONG_LONG_MIN;
long long expo(long long x, long long n, long long M) {
  if (n == 0)
    return 1;
  else if (n % 2 == 0)
    return (expo((x * x) % M, n / 2, M)) % M;
  else
    return (x * expo((x * x) % M, (n - 1) / 2, M)) % M;
}
bool sortbysec(pair<pair<long long, long long>, long long> p1,
               pair<pair<long long, long long>, long long> p2) {
  if (p1.first.first == p2.first.first)
    return p1.first.second > p2.first.second;
  return p1.first.first < p2.first.first;
}
long long solve(char cc) {
  if (cc == 'f')
    return 1;
  else if (cc == 'e')
    return 2;
  else if (cc == 'd')
    return 3;
  else if (cc == 'a')
    return 4;
  else if (cc == 'b')
    return 5;
  else
    return 6;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long i, j, k, a, b, c, t, x, y, n, m, z, flag = 0, ans = 0, sum = 0;
  t = 1;
  while (t--) {
    string st, pt;
    cin >> st;
    n = st.length();
    char cc = st[n - 1];
    st = st.substr(0, n - 1);
    x = stoll(st);
    y = (x - 1) / 4;
    ans = y * 16ll;
    long long r = x % 4;
    if (r == 1 || r == 3) {
      ans += solve(cc);
    } else {
      ans += 7;
      ans += solve(cc);
    }
    cout << ans;
  }
  return 0;
}
