import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const K = readLong;
      auto A = new long[N];
      foreach (i; 0 .. N) {
        A[i] = readLong;
      }
      
      long lo = A.minElement, hi = A[0] + K + 1;
      for (; lo + 1 < hi; ) {
        const mid = (lo + hi) / 2;
        long cost;
        long off;
        foreach (i; 0 .. N) {
          const a = A[i] + off;
          if (a < mid) {
            const t = ((mid - a) + (i + 1) - 1) / (i + 1);
            cost += t;
            if (cost > K) {
              break;
            }
            off += t * (i + 1);
          }
        }
        ((cost <= K) ? lo : hi) = mid;
      }
      writeln(lo);
    }
  } catch (EOFException e) {
  }
}