a = "MARTA"
b = "TOR"
c = "GPJNP"
def szyfr(x,y):
    chujcik = ""
    for i in range(len(x)):
        sumka = ord(x[i]) + ord(y[i%len(y)]) - 64
        if(sumka > 90):
            sumka -= 26
        chujcik += chr(sumka)
    return chujcik
def deszyfr(x,y):
    chujcik = ""
    for i in range(len(x)):
        sumka = ord(x[i]) - ord(y[i%len(y)]) + 64
        if(sumka < 65):
            sumka += 26
        chujcik += chr(sumka)
    return chujcik
print( szyfr(a,b) )
print( deszyfr(c,b) )