cat chars.py```f = open("flag.txt", "r")flag = ""
lines = f.readlines()
for i in range(0,len(lines)):  line = lines[i]  flag += line[i]print flag```
python chars.py
cmFkYXJ7Y2hhcl9hZnRlcl9jaGFyX2dpdmVfZmxhZ30
b64decode(cmFkYXJ7Y2hhcl9hZnRlcl9jaGFyX2dpdmVfZmxhZ30) = radar{char_after_char_give_flag}