x= "jhjhkvvmadam" y = [] for i in range(len(x)): for j in range(i+1,len(x)): if x[i:j+1]==x[i:j+1][::-1]: y.append(x[i:j+1]) print i, j print y z = [len(i) for i in y] print y[z.index(max(z))]