def main():
    print "Hello!"
    print "This program takes a DNA sequence and transcripts it to RNA sequence."

    dna=raw_input("Please, input a DNA sequence (it should consist of A,C,G, and T only):")

    check = True # used to indicate if a symbol other than A,C,G or T is met
    # in DNA sequence

    rna=str() # initialize RNA sequence to empty string

    for char in dna:
        if (char != "A" and char != "C" and char != "G" and char != "T" ):
            check=False
            break
        elif char == "A":
            n="U"
        elif char == "C":
            n="G"
        elif char == "G":
            n="C"
        else:
            n="A"
        rna = rna + n  #appending the corresponding nucleotide to RNA sequence
            

    if check == True:
        print "The provided DNA:",dna
        print "The transcipted RNA:",rna
    else:
        print "The provided DNA sequence has at lease one symbol other than A,C,G, or T"
        print "Have a good day!"

main()