lst = "aaabbc"

ans = ""
c = 1

for n in range(1, len(lst)):
    if lst[n] == lst[n - 1]:
        c += 1
    else:
        ans += str(c) + lst[n - 1]
        c = 1

ans += str(c) + lst[-1]

compressed = ans
print(compressed)

decompressed = ""
num = ""

for ch in compressed:
    if ch.isdigit():
        num += ch
    else:
        decompressed += ch * int(num)
        num = ""

print(decompressed)