def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    K = int(input[idx])
    idx += 1
    S = input[idx]
    
    # Compute for each j, the result of the reduction of S[j:j + (N-K +1)]
    result = []
    for j in range(K):
        end = j + (N - K + 1)
        current_layer = S[j:end]
        
        # Compute the reduction
        while len(current_layer) > 1:
            next_layer = []
            for i in range(len(current_layer) - 1):
                a = int(current_layer[i])
                b = int(current_layer[i+1])
                if a == 1 and b == 1:
                    next_layer.append('0')
                else:
                    next_layer.append('1')
            current_layer = ''.join(next_layer)
        result.append(current_layer[0])
    
    print(''.join(result))

if __name__ == '__main__':
    main()