#import <stdio.h>

int main(int argc, char *argv[]) {
	int N,S;
	scanf("%d %d",&N,&S);
	int E = S + N - 1;
	int a;
	if (S<0&&E>0) {
		a = (S+E)*N/2;
	}else if (S>=0){
		a = (S+1+E)*(N-1)/2;
	} else {
		a = (S+E-1)*(N-1)/2;
	}
	printf("%d",a);
}
; ModuleID = '/data/TheStack_IR/OJ_Samples/Collated/ObjectiveC/Source_251/source.m'
source_filename = "/data/TheStack_IR/OJ_Samples/Collated/ObjectiveC/Source_251/source.m"
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"

@.str = private unnamed_addr constant [6 x i8] c"%d %d\00", align 1
@.str.1 = private unnamed_addr constant [3 x i8] c"%d\00", align 1

; Function Attrs: minsize nofree nounwind optsize uwtable
define dso_local i32 @main(i32 noundef %argc, ptr nocapture noundef readnone %argv) local_unnamed_addr #0 {
entry:
  %N = alloca i32, align 4
  %S = alloca i32, align 4
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %N) #3
  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %S) #3
  %call = call i32 (ptr, ...) @__isoc99_scanf(ptr noundef nonnull @.str, ptr noundef nonnull %N, ptr noundef nonnull %S) #4
  %0 = load i32, ptr %S, align 4, !tbaa !5
  %1 = load i32, ptr %N, align 4, !tbaa !5
  %add = add nsw i32 %1, %0
  %sub = add nsw i32 %add, -1
  %cmp = icmp slt i32 %0, 0
  %cmp1 = icmp sgt i32 %add, 1
  %or.cond = select i1 %cmp, i1 %cmp1, i1 false
  br i1 %or.cond, label %if.then, label %if.else

if.then:                                          ; preds = %entry
  %add2 = add nsw i32 %sub, %0
  %mul = mul nsw i32 %add2, %1
  br label %if.end16

if.else:                                          ; preds = %entry
  %cmp3 = icmp sgt i32 %0, -1
  br i1 %cmp3, label %if.then4, label %if.else10

if.then4:                                         ; preds = %if.else
  %add6 = add i32 %add, %0
  %sub7 = add nsw i32 %1, -1
  %mul8 = mul nsw i32 %add6, %sub7
  br label %if.end16

if.else10:                                        ; preds = %if.else
  %add11 = add nsw i32 %sub, %0
  %sub12 = add nsw i32 %add11, -1
  %sub13 = add nsw i32 %1, -1
  %mul14 = mul nsw i32 %sub12, %sub13
  br label %if.end16

if.end16:                                         ; preds = %if.then4, %if.else10, %if.then
  %a.0.in = phi i32 [ %mul, %if.then ], [ %mul8, %if.then4 ], [ %mul14, %if.else10 ]
  %a.0 = sdiv i32 %a.0.in, 2
  %call17 = call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str.1, i32 noundef %a.0) #4
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %S) #3
  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %N) #3
  ret i32 0
}

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #1

; Function Attrs: minsize nofree nounwind optsize
declare noundef i32 @__isoc99_scanf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

; Function Attrs: minsize nofree nounwind optsize
declare noundef i32 @printf(ptr nocapture noundef readonly, ...) local_unnamed_addr #2

; Function Attrs: mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #1

attributes #0 = { minsize nofree nounwind optsize uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #1 = { mustprogress nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
attributes #2 = { minsize nofree nounwind optsize "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes #3 = { nounwind }
attributes #4 = { minsize optsize }

!llvm.linker.options = !{}
!llvm.module.flags = !{!0, !1, !2, !3}
!llvm.ident = !{!4}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{i32 8, !"PIC Level", i32 2}
!2 = !{i32 7, !"PIE Level", i32 2}
!3 = !{i32 7, !"uwtable", i32 2}
!4 = !{!"Ubuntu clang version 18.0.0 (++20231007042255+8abb2ace888b-1~exp1~20231007042414.1230)"}
!5 = !{!6, !6, i64 0}
!6 = !{!"int", !7, i64 0}
!7 = !{!"omnipotent char", !8, i64 0}
!8 = !{!"Simple C/C++ TBAA"}
