#include <bits/stdc++.h>
using namespace std;
class BigNum {
 private:
  int a[500];
  int len;

 public:
  BigNum() {
    len = 1;
    memset(a, 0, sizeof(a));
  }
  BigNum(const int);
  BigNum operator*(const BigNum &) const;
  BigNum operator+(const BigNum &) const;
  void print();
};
BigNum::BigNum(const int b) {
  int c, d = b;
  len = 0;
  memset(a, 0, sizeof(a));
  while (d > 9999) {
    c = d - (d / (9999 + 1)) * (9999 + 1);
    d = d / (9999 + 1);
    a[len++] = c;
  }
  a[len++] = d;
}
BigNum BigNum::operator+(const BigNum &T) const {
  BigNum t(*this);
  int i, big;
  big = T.len > len ? T.len : len;
  for (i = 0; i < big; i++) {
    t.a[i] += T.a[i];
    if (t.a[i] > 9999) {
      t.a[i + 1]++;
      t.a[i] -= 9999 + 1;
    }
  }
  if (t.a[big] != 0)
    t.len = big + 1;
  else
    t.len = big;
  return t;
}
BigNum BigNum::operator*(const BigNum &T) const {
  BigNum ret;
  int i, j, up;
  int temp, temp1;
  for (i = 0; i < len; i++) {
    up = 0;
    for (j = 0; j < T.len; j++) {
      temp = a[i] * T.a[j] + ret.a[i + j] + up;
      if (temp > 9999) {
        temp1 = temp - temp / (9999 + 1) * (9999 + 1);
        up = temp / (9999 + 1);
        ret.a[i + j] = temp1;
      } else {
        up = 0;
        ret.a[i + j] = temp;
      }
    }
    if (up != 0) ret.a[i + j] = up;
  }
  ret.len = i + j;
  while (ret.a[ret.len - 1] == 0 && ret.len > 1) ret.len--;
  return ret;
}
void BigNum::print() {
  int i;
  cout << a[len - 1];
  for (i = len - 2; i >= 0; i--) {
    cout.width(4);
    cout.fill('0');
    cout << a[i];
  }
  cout << endl;
}
int main() {
  BigNum b(16), b1(1), b2(2), b3(3), b4(4), b5(5), b6(6), b7(7);
  char s[20001];
  int d, i, j;
  while (~scanf("%s", s)) {
    long long ans = 0;
    d = strlen(s) - 1;
    long long n = 0, tep = 1;
    for (i = d - 1; i >= 0; i--) {
      n += tep * (s[i] - '0');
      tep *= 10;
    }
    char c = s[d];
    long long q = (n - 1) / 4;
    ans = ans + q * (16);
    n %= 4;
    n %= 2;
    if (n == 0) ans = ans + 7;
    if (c == 'a')
      ans = ans + 4;
    else if (c == 'b')
      ans = ans + 5;
    else if (c == 'c')
      ans = ans + 6;
    else if (c == 'd')
      ans = ans + 3;
    else if (c == 'e')
      ans = ans + 2;
    else if (c == 'f')
      ans = ans + 1;
    printf("%I64d\n", ans);
  }
  return 0;
}
