type
    list=array[1..2]of integer;
var
   a:array[0..100]of list;
   f1:list;
   f:array[0..100]of longint;
   i,j,k,m,n,max:longint;
begin
     fillchar(a,sizeof(a),0);
     readln(m,n);
     read(k);
     for i:=1 to k do
         read(a[i][1],a[i][2]);
     for i:=1 to k-1 do
         for j:=1 to k-i do
             if (a[j][1]>a[j+1][1]) or (a[j][2]>a[j+1][2]) then begin
                f1:=a[j];
                a[j]:=a[j+1];
                a[j+1]:=f1;
             end;
     f[0]:=0;
     for i:=1 to k do begin
         max:=0;
         for j:=0 to i do begin
             if (a[j][1]<a[i][1]) and (a[j][2]<a[i][2]) then if f[j]
+1>max then max:=f[j]+1;
         end;
         f[i]:=max;
     end;
     writeln((m+n-2*f[k]+sqrt(2)*f[k])*100:0:0);
end.