Run length encoding (RLE) is a lossless compression algorithm that represents consecutive repeating data values as a count and data pair.

For example, the character sequence AAAAABBBCC can be represented as 5 A 3 B 2 C because there are five 'A's, followed by three 'B's, and finally two 'C's.

The algorithm below in Figure 1 is designed to output the RLE pairs for any text sequence entered by a user.

Three parts of the pseudocode labelled L1, L2, and L3 are missing.

• Note that string indexing starts at zero.

Figure 1

sequence ← USERINPUT
index ← 0
current_run ← 1
WHILE index < LEN(sequence) - 1
    IF sequence[index] == sequence[index + 1] THEN
        current_run ← current_run + 1
    ELSE
        OUTPUT current_run
        OUTPUT sequence[index]
        current_run ← L1
    ENDIF
    L3
ENDWHILE
OUTPUT current_run
OUTPUT sequence[index]

Which code should be written at point L3 of the algorithm to ensure the sequence is processed correctly without causing an infinite loop?