program nark;
var
a:array[1..100000]of integer;
n,i,m,j,ans:longint;
begin
assign(input,'mark.in');
assign(output,'mark.out');
reset(input); rewrite(output);
readln(n,m);
for i:=1 to n do readln(a[i]);
readln(ans);
j:=1;
for i:=1 to n do if a[i]>a[ans] then j:=j+1;
i:=1;
while (((i-1)*(n div m)+1>j)or(i*(n div m)<j)) and(i<=m) do I:=I+1;
writeln(i);
close(input); close(output);
end.