#include <bits/stdc++.h>
using namespace std;
bool cmp(const pair<char, int>& x, const pair<char, int>& y) {
  int u = max(x.first - 'a', 'z' - x.first);
  int v = max(y.first - 'a', 'z' - y.first);
  return u > v;
}
int main() {
  if (0 & 1) freopen("input", "r", stdin);
  if (0 & 2) freopen("output", "w", stdout);
  int n, k;
  scanf("%d %d", &n, &k);
  vector<pair<char, int> > a(n);
  int id = 0;
  for (auto& e : a) {
    scanf(" %c", &e.first);
    e.second = id++;
  }
  sort(a.begin(), a.end(), cmp);
  string ans(n, ' ');
  for (auto& e : a) {
    int u = e.first - 'a', v = 'z' - e.first, cur;
    if (u > v) {
      cur = min(k, u);
      ans[e.second] = e.first - cur;
    } else {
      cur = min(k, v);
      ans[e.second] = e.first + cur;
    }
    k -= cur;
  }
  if (k)
    printf("-1\n");
  else
    printf("%s\n", ans.c_str());
  return 0;
}
