program book;var  a,f,g:array[0..200001]of qword;  l,r:array[0..100001]of longint;  n,i,m:longint; sum,ans:qword;procedure qsort(l,h:longint);var i,j,t:longint; m:qword;begin i:=l; j:=h; m:=a[(i+j) div 2]; repeatwhile a[i]<m do inc(i);while m<a[j] do dec(j);if i<=j then  begin   t:=a[i]; a[i]:=a[j]; a[j]:=t;inc(i); dec(j);  end;  until i>j; if i<h then qsort(i,h); if j>l then qsort(l,j);  end;function make(x:longint):longint;var l,r,mid,ans:longint;begin  l:=1;r:=m;  while l<=r do   begin     mid:=(l+r) div 2;     if f[mid]<=x then begin ans:=mid; l:=mid+1; end      else begin r:=mid-1; end;   end;  exit(ans);end;procedure fry;var i:longint;begin  qsort(1,2*n);  a[0]:=-1;  for i:=1 to 2*n do   if a[i]<>a[i-1] then begin inc(m); f[m]:=a[i]; end;  for i:=1 to n do   begin     l[i]:=make(l[i]); r[i]:=make(r[i]);   end;end;begin  assign(input,‘book.in‘);reset(input);assign(output,‘book.out‘);rewrite(output);  readln(n); m:=0;  for i:=1 to n do   begin      readln(l[i],r[i]);      a[i*2-1]:=l[i];  a[i*2]:=r[i];   end;  fry;  for i:=1 to n do   begin     inc(g[l[i]]); dec(g[r[i]+1]);   end;  for i:=1 to m do   begin     inc(sum,g[i]);     if sum*f[i]>ans then ans:=sum*f[i];   end;  writeln(ans);  close(input); close(output);end.