Character-level substitution is a surprisingly deep Unix skill. Transcription is the
simplest possible example — swap every T for a U — but the same tool does case conversion, complement
generation, and character deletion. Once you have used tr to build a reverse complement in a single
pipeline you understand why command-line bioinformatics survived the arrival of Python.
Statement
A single DNA sequence arrives on standard input.
Transcribe it into RNA by replacing every occurrence of T with U, leaving all other characters
unchanged.
Print the resulting RNA sequence on one line.
Input — read from standard input
Variable
Type
Description
dna
line 1
str
The DNA sequence to transcribe
1 <= len(dna) <= 5000, uppercase A, C, G, T only
These variables are already read for you in the starter code on the right.
Output
str
the transcribed RNA sequence on one line
Sample Cases
Sample 1
Input
GATGGAACTTGACTACGTAACGTTTTT
Expected Output
GAUGGAACUUGACUACGUAACGUUUUU
Every thymine becomes uracil; all other bases are untouched.
Sample 2
Input
ACGT
Expected Output
ACGU
A minimal four-base sequence.
Submit also runs your code against 3 hidden test cases.
Hidden inputs are never shown — if one fails you'll get its number and a description of the
mismatch, not the data.
Constraints
Only uppercase T is replaced; no other character changes
The output has exactly the same length as the input
Input contains only uppercase A, C, G, T
Solutions must read standard input and write to standard output only