def main():
    import sys
    input = sys.stdin.read().split()
    N = int(input[0])
    K = int(input[1])
    S = input[2]
    
    def compute_row(prev_row, m):
        row = prev_row
        for _ in range(m):
            new_row = []
            for i in range(len(row) - 1):
                a = row[i]
                b = row[i + 1]
                if a == '1' and b == '1':
                    new_row.append('0')
                else:
                    new_row.append('1')
            row = new_row
        return ''.join(row)
    
    m = N - K
    current_row = list(S)
    for _ in range(m):
        new_row = []
        for i in range(len(current_row) - 1):
            a = current_row[i]
            b = current_row[i + 1]
            if a == '1' and b == '1':
                new_row.append('0')
            else:
                new_row.append('1')
        current_row = new_row
    
    print(''.join(current_row[:K]))

if __name__ == "__main__":
    main()