M = "afkpuzbglqv.chmrw?dinsx!ejoty "
while True:
    try:
        s = raw_input()
        l = len(s)
        mes = ""
        if l&1:
            1/0
        for i in xrange(l/2):
            i1 = int(s[2*i])-1; i2 = int(s[2*i+1])-1
            if 0<=i1<=5 and 0<=i2<=4:
                mes += M[i1 + i2*6]
            else:
                1/0
        print mes
    except EOFError:
        break
    except Exception:
        print "NA"
        continue