starry, 242 bytes

Result

AC

Duration

586ms

Code [DL]

                               + ` +   '      +  '   `      + * + ,                                            + *  + *                               +    *                                                                      +* .      + '  `

Disassembly

[[:push, 26],
 [:label, 1],
 [:dup],
 [:jump, 3],
 [:push, 1],
 [:jump, 2],
 [:label, 3],
 [:push, 1],
 [:-],
 [:dup],
 [:char_in],
 [:push, 39],
 [:-],
 [:swap],
 [:-],
 [:push, 26],
 [:%],
 [:push, 65],
 [:+],
 [:char_out],
 [:push, 1],
 [:jump, 1],
 [:label, 2]]

stdin

GQSIQTOABCFSHBFWNFGZTVQQYU

stdout

HSVMVZVIKMQEUPUMEXZTORNOXU

stderr

strace