if matriu_inicial[num_files//2][num_files//2]=="x":
                contador=contador
            else:
                contador=contador+1

def omple_simplista(xifra,num_files) :
    matriu_inicial=[['' for i in range(num_files)] for i in range(num_files)]
    contador=0
    for a in range(num_files):
        for b in range(num_files):
            matriu_inicial[a][b]=int(xifra+contador)
            contador=contador+1
    return matriu_inicial

num_files = int(input(" quantes files "))
xifra= int(input(" primer element "))

matriu=[]
matriu=omple_simplista(xifra,num_files)

numero_columna_inicial=num_files//2-1
numero_columna_final=num_files//2+1

for d in matriu:
    matriu[num_files//2][num_files//2]="x"
    
for q in range (num_files//2+1,num_files,1):
    for w in range (numero_columna_inicial,numero_columna_final+1,1):
        matriu[q][w]="x"
    numero_columna_inicial=numero_columna_inicial-1
    numero_columna_final=numero_columna_final+1

for a in matriu:
    print(a)