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.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; }
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;
debug {
  int K;
  string S;
}

bool Ask(int[] as) {
  bool ret;
  debug {
    writeln("Ask ", as);
    int cnt;
    foreach (a; as) {
      if (S[a] == '1') {
        ++cnt;
      }
    }
    ret = (cnt == K);
  } else {
    writeln("? ", as.length);
    foreach (h, a; as) {
      if (h > 0) write(" ");
      write(a + 1);
    }
    writeln();
    stdout.flush;
    const res = readInt();
    ret = (res != 0);
  }
  return ret;
}

void main() {
  N = readInt();
  debug {
    S = readToken();
    K = S.count('1');
  }
  
  int lo = 1, hi = N;
  for (; lo + 1 < hi; ) {
    const mid = (lo + hi) / 2;
    if (Ask(iota(mid).array)) {
      hi = mid;
    } else {
      lo = mid;
    }
  }
  int[] ans;
  foreach (i; 0 .. hi) {
    auto as = iota(i).array ~ iota(i + 1, hi).array;
    if (as.length >= 2 && Ask(as)) {
      // safe
    } else {
      ans ~= i;
    }
  }
  writeln("! ", ans.length);
  foreach (h, i; ans) {
    if (h > 0) write(" ");
    write(i + 1);
  }
  writeln();
  stdout.flush;
}