def compress_string(s: str) -> str:
    new_s = ""
    count = 0
    len_new_s = 0
    for i in range(len(s)):
        if new_s == "":
            new_s += s[i]
            count +=1
            len_new_s +=1
        elif new_s[len_new_s-1] == s[i]:
            count += 1
        else:
            if count != 1:
                new_s += str(count)
                len_new_s += 1
            new_s += s[i]
            count = 1
            len_new_s += 1
    if count != 1:
        new_s += str(count)
    return(new_s)



if __name__ == '__main__':
    print(compress_string("aaabbc") + " a3b2c")
    print(compress_string("abc") + " abc")
    print(compress_string("aabbaa") + " a2b2a2")
    print(compress_string("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbb") + " a2b2a2")