MAIN    START
        PUSH    0,GR1
        PUSH    0,GR2
        LAD     GR1,IBUF
        LAD     GR2,LEN
        SVC     1
        POP     GR2
        POP     GR1
        IN      IBUF,LEN
        OUT     IBUF,LEN
        RET
IBUF    DS      100
LEN     DC      1
        END