{
TASK:books
LANG:Pascal
}
var a:array[0..101,0..201,0..2] of qword;
    b:array[0..201] of longint;
    c:array[0..201] of longint;
    d:array[0..201] of qword;
    n,m,i,j,k,koef:longint;
    p,q,r,r2:qword;
Function Sum(s,s1,u:longint):qword;
var t,t1:longint;
    f,r1:qword;
begin
   t1:=u+1;
   f:=0;
   for t:=s to s1 do
      begin
        r1:=b[t];
        r1:=r1*c[t1];
        f:=f+r1;
        inc(t1);
      end;
   Sum:=f;
end;
begin
   readln(m,n);
   for i:=1 to m do read(b[i]);
   readln;
   for i:=1 to m do read(c[i]);
   for i:=1 to m do
      begin
         a[1,i,2]:=i;
         r2:=b[i];
         r2:=r2*c[i];
         a[1,i,1]:=a[1,i-1,1]+r2;
      end;
   for i:=2 to n do
       begin
           for j:=1 to m do
              begin
                 koef:=0;
                 p:=a[i-1,j,1];
                 for k:=1 to j-1 do
                    begin
                       r:=Sum(k+1,j,0);
                       r:=r+a[i-1,k,1];
                       if r<p then
                          begin
                             p:=r;
                             koef:=j-k+a[i,k,2];
                          end;
                    end;
              a[i,j,1]:=p;
              a[i,j,2]:=koef;
              end;
       end;
   writeln(a[n,m,1]);

end.
