integer N,M
integer li,ri
integer l,r
read*,N,M
l=1
r=N
do i=1,M
  read*,li,ri
  l=max(li,l)
  r=min(ri,r)
end do
print"(I0)",max(0,r-l+1)
end
; 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"

@_QQcl.cc050ede05ac3cb10fadbc9357d68d04 = linkonce constant [73 x i8] c"/home/ubuntu/Downloads/TheStack_IR/Collated/Fortran/Source_4222/source.f\00"
@_QQcl.28493029 = linkonce constant [4 x i8] c"(I0)"
@_QQEnvironmentDefaults = local_unnamed_addr constant ptr null

define void @_QQmain() local_unnamed_addr {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = tail call ptr @_FortranAioBeginExternalListInput(i32 -1, ptr nonnull @_QQcl.cc050ede05ac3cb10fadbc9357d68d04, i32 4)
  %6 = call i1 @_FortranAioInputInteger(ptr %5, ptr nonnull %3, i32 4)
  %7 = call i1 @_FortranAioInputInteger(ptr %5, ptr nonnull %2, i32 4)
  %8 = call i32 @_FortranAioEndIoStatement(ptr %5)
  %9 = load i32, ptr %3, align 4, !tbaa !3
  %10 = load i32, ptr %2, align 4, !tbaa !3
  %11 = icmp sgt i32 %10, 0
  br i1 %11, label %.lr.ph.preheader, label %._crit_edge

.lr.ph.preheader:                                 ; preds = %0
  %12 = zext i32 %10 to i64
  br label %.lr.ph

.lr.ph:                                           ; preds = %.lr.ph.preheader, %.lr.ph
  %13 = phi i64 [ %22, %.lr.ph ], [ %12, %.lr.ph.preheader ]
  %.08 = phi i32 [ %21, %.lr.ph ], [ %9, %.lr.ph.preheader ]
  %.057 = phi i32 [ %19, %.lr.ph ], [ 1, %.lr.ph.preheader ]
  %14 = call ptr @_FortranAioBeginExternalListInput(i32 -1, ptr nonnull @_QQcl.cc050ede05ac3cb10fadbc9357d68d04, i32 8)
  %15 = call i1 @_FortranAioInputInteger(ptr %14, ptr nonnull %1, i32 4)
  %16 = call i1 @_FortranAioInputInteger(ptr %14, ptr nonnull %4, i32 4)
  %17 = call i32 @_FortranAioEndIoStatement(ptr %14)
  %18 = load i32, ptr %1, align 4, !tbaa !3
  %19 = call i32 @llvm.smax.i32(i32 %18, i32 %.057)
  %20 = load i32, ptr %4, align 4, !tbaa !3
  %21 = call i32 @llvm.smin.i32(i32 %20, i32 %.08)
  %22 = add nsw i64 %13, -1
  %23 = icmp ugt i64 %13, 1
  br i1 %23, label %.lr.ph, label %._crit_edge.loopexit

._crit_edge.loopexit:                             ; preds = %.lr.ph
  %24 = sub i32 1, %19
  br label %._crit_edge

._crit_edge:                                      ; preds = %._crit_edge.loopexit, %0
  %.05.lcssa = phi i32 [ 0, %0 ], [ %24, %._crit_edge.loopexit ]
  %.0.lcssa = phi i32 [ %9, %0 ], [ %21, %._crit_edge.loopexit ]
  %25 = call ptr @_FortranAioBeginExternalFormattedOutput(ptr nonnull @_QQcl.28493029, i64 4, ptr null, i32 -1, ptr nonnull @_QQcl.cc050ede05ac3cb10fadbc9357d68d04, i32 12)
  %26 = add i32 %.05.lcssa, %.0.lcssa
  %27 = call i32 @llvm.smax.i32(i32 %26, i32 0)
  %28 = call i1 @_FortranAioOutputInteger32(ptr %25, i32 %27)
  %29 = call i32 @_FortranAioEndIoStatement(ptr %25)
  ret void
}

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

declare i1 @_FortranAioInputInteger(ptr, ptr, i32) local_unnamed_addr

declare i32 @_FortranAioEndIoStatement(ptr) local_unnamed_addr

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

declare i1 @_FortranAioOutputInteger32(ptr, i32) local_unnamed_addr

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.smax.i32(i32, i32) #0

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare i32 @llvm.smin.i32(i32, i32) #0

attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

!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"}
