Program generator;
uses crt;
var k,m,b,n:longint;
a,x:array [1..30] of integer;
f1,f2:text;
xn:integer;
begin
clrscr;
assign (f1,'input.txt');
reset (f1);
read (f1,k);
readln (f1,m);
for i:=1 to k do
read (f1,a[i]);
read (f1,b);
for i:=1 to k do
read (f1,x[i]);
read (f1,n);
close (f1);
for i:=1 to k do
begin
xn:=xn+(a[n]*x[n-i]) mod m;
end;
xn:=xn+b mod m;
assign (f2,'output.txt');
rewrite (f2);
write (f2,xn);
close (f2);
end.