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; } 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)); } void main() { try { for (; ; ) { const N = readInt; const K = readInt; const S = readToken; int n = N; auto cs = S.dup; if ((n - K) % 2 != 0) { auto ccs = new char[n - 1]; foreach (i; 0 .. n - 1) { ccs[i] = (cs[i] == '1' && cs[i + 1] == '1') ? '0' : '1'; } --n; cs = ccs; } debug { writeln("n = ", n); writeln("cs = ", cs); } auto ans = new char[K]; ans[] = '0'; for (int i = 0, j; i < n; i = j) { for (j = i; j < n && cs[i] == cs[j]; ++j) {} if (cs[i] == '1' && (n - K == 0 || j - i >= 2)) { const l = max(i - (n - K) / 2, 0); const r = min(j - (n - K) / 2, K); if (l < r) { ans[l .. r] = '1'; } } } writeln(ans); } } catch (EOFException e) { } }