import std.conv, std.functional, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, 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; }
real readReal() { return readToken.to!real; }

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)); }


int N, K;
int[] A;

void main() {
  try {
    for (; ; ) {
      N = readInt();
      K = readInt();
      A = new int[N];
      foreach (i; 0 .. N) {
        A[i] = readInt();
      }
      
      auto ps = new Tuple!(int, int)[N];
      foreach (i; 0 .. N) {
        ps[i] = tuple(A[i], i);
      }
      ps.sort!"a > b";
      
      int[] ans;
      foreach (k; 0 .. ps[0][0]) {
        foreach (j; 0 .. N) {
          const i = ps[j][1];
          if (k < A[i]) {
            ans ~= i;
          }
        }
      }
      debug {
        writeln("ans = ", ans);
      }
      
      auto app = new bool[N];
      int now;
      int magic;
      foreach (i; ans) {
        if (!app[i]) {
          app[i] = true;
          if (++now == N) {
            ++magic;
            app[] = false;
            app[i] = true;
            now = 1;
          }
        }
      }
      if (magic <= K) {
        writeln(-1);
      } else {
        writeln(ans.length);
        foreach (idx, i; ans) {
          if (idx > 0) {
            write(" ");
          }
          write(i + 1);
        }
        writeln();
      }
    }
  } catch (EOFException e) {
  }
}
