program speedrun
    implicit none
    character(100)::S
    integer::ANS=0,L
    integer::i
    read*,S
    L=len_trim(S)
    do i=1,L/2
        if(S(i:i)/=S(L-i+1:L-i+1))ANS=ANS+1
    end do
    print"(i0)",ANS
end program speedrun
; ModuleID = 'FIRModule'
source_filename = "FIRModule"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"

@_QFEans = internal unnamed_addr global i32 0
@_QFEs = internal global [100 x i8] undef
@_QQcl.c750e80a12cb725ce1df646a113584fe = linkonce constant [73 x i8] c"/home/ubuntu/Downloads/TheStack_IR/Collated/Fortran/Source_2856/source.f\00"
@_QQcl.28693029 = linkonce constant [4 x i8] c"(i0)"
@_QQEnvironmentDefaults = local_unnamed_addr constant ptr null

define void @_QQmain() local_unnamed_addr {
  %1 = tail call ptr @_FortranAioBeginExternalListInput(i32 -1, ptr nonnull @_QQcl.c750e80a12cb725ce1df646a113584fe, i32 6)
  %2 = tail call i1 @_FortranAioInputAscii(ptr %1, ptr nonnull @_QFEs, i64 100)
  %3 = tail call i32 @_FortranAioEndIoStatement(ptr %1)
  br label %4

4:                                                ; preds = %0, %4
  %5 = phi i64 [ 99, %0 ], [ %9, %4 ]
  %6 = getelementptr [100 x [1 x i8]], ptr @_QFEs, i64 0, i64 %5
  %7 = load i8, ptr %6, align 1, !tbaa !3
  %8 = icmp eq i8 %7, 32
  %9 = add nsw i64 %5, -1
  %10 = icmp ne i64 %5, 0
  %11 = and i1 %8, %10
  br i1 %11, label %4, label %12

12:                                               ; preds = %4
  %13 = trunc i64 %5 to i32
  %14 = add i32 %13, 1
  %15 = select i1 %8, i32 0, i32 %14
  %16 = icmp sgt i32 %15, 1
  br i1 %16, label %.lr.ph, label %._crit_edge

.lr.ph:                                           ; preds = %12
  %17 = lshr i32 %15, 1
  %18 = add nuw i32 %15, 1
  %narrow = add nuw nsw i32 %17, 1
  %19 = zext i32 %narrow to i64
  br label %20

20:                                               ; preds = %.lr.ph, %32
  %indvars.iv = phi i64 [ 1, %.lr.ph ], [ %indvars.iv.next, %32 ]
  %21 = add nsw i64 %indvars.iv, -1
  %22 = getelementptr [100 x [1 x i8]], ptr @_QFEs, i64 0, i64 %21
  %23 = trunc i64 %indvars.iv to i32
  %24 = sub i32 %18, %23
  %25 = sext i32 %24 to i64
  %26 = add nsw i64 %25, -1
  %27 = getelementptr [100 x [1 x i8]], ptr @_QFEs, i64 0, i64 %26
  %28 = tail call i32 @_FortranACharacterCompareScalar1(ptr %22, ptr %27, i64 1, i64 1)
  %.not = icmp eq i32 %28, 0
  br i1 %.not, label %32, label %29

29:                                               ; preds = %20
  %30 = load i32, ptr @_QFEans, align 4, !tbaa !3
  %31 = add i32 %30, 1
  store i32 %31, ptr @_QFEans, align 4, !tbaa !3
  br label %32

32:                                               ; preds = %29, %20
  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
  %exitcond.not = icmp eq i64 %indvars.iv.next, %19
  br i1 %exitcond.not, label %._crit_edge, label %20

._crit_edge:                                      ; preds = %32, %12
  %33 = tail call ptr @_FortranAioBeginExternalFormattedOutput(ptr nonnull @_QQcl.28693029, i64 4, ptr null, i32 -1, ptr nonnull @_QQcl.c750e80a12cb725ce1df646a113584fe, i32 11)
  %34 = load i32, ptr @_QFEans, align 4, !tbaa !3
  %35 = tail call i1 @_FortranAioOutputInteger32(ptr %33, i32 %34)
  %36 = tail call i32 @_FortranAioEndIoStatement(ptr %33)
  ret void
}

declare ptr @_FortranAioBeginExternalListInput(i32, ptr, i32) local_unnamed_addr

declare i1 @_FortranAioInputAscii(ptr, ptr, i64) local_unnamed_addr

declare i32 @_FortranAioEndIoStatement(ptr) local_unnamed_addr

declare i32 @_FortranACharacterCompareScalar1(ptr, ptr, i64, i64) local_unnamed_addr

declare ptr @_FortranAioBeginExternalFormattedOutput(ptr, i64, ptr, i32, ptr, i32) local_unnamed_addr

declare i1 @_FortranAioOutputInteger32(ptr, i32) local_unnamed_addr

!llvm.module.flags = !{!0, !1, !2}

!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{!4, !4, i64 0}
!4 = !{!"any data access", !5, i64 0}
!5 = !{!"any access", !6, i64 0}
!6 = !{!"Flang Type TBAA Root"}
