var a,k,j,x,i,n,m,y:integer;
    f,g:text;
    v:array[1..101]of integer;
begin
assign(f,'factoriale.in'); reset(f);
assign(g,'factoriale.out'); rewrite(g);
read (f,n,K);

a:=0;
m:=1;
for i:=1 to n do begin             
   read(f,x);
   v[i]:=x;
   end;
for j:=i to n do
       for i:=1 to v[j] do
                    m:=m*i;
while y<m do begin
     a:=a+1;
     y:=a;
     for j:=1 to k do
         y:=y*y;
     end;
write(g,a);
close(f);
close(g);
end.