const maxn=20;
var
a:array[1..maxn] of integer;
n,k,i,j,count:integer;
x:array[1..maxn] of longint;
sum:longint;
function prime(n:longint):boolean;
var i:integer;flag:boolean;
begin
if n=2 then prime:=true
else if n mod 2=0 then prime:=false
else
begin
flag:=true;i:=3;
while flag and (i<=n div 2) do begin
if n mod i=0 then flag:=false;i:=i+2;end;
prime:=flag;
end;
end;
begin
readln(n,k);
for i:=1 to n do read(x);
count:=0;
for i:=1 to k do a:=i;
i:=k;
while (i>0) do begin
sum:=0;
for i:=1 to k do sum:=sum+x[a];
if prime(sum) then
count:=count+1;
i:=k;
while (i>0) and (a=n-k+i) do i:=i-1;
if (i>0) then begin
a:=a+1;
for j:=i+1 to k do a[j]:=a[j-1]+1;end;
end;
writeln(count);
end.
