1. program fakto;
uses wincrt;
function factorial(n:integer):longint;
begin
if(n=0)then
factorial:=1
else
factorial:=n*factorial(n-1);
end;
function permutasi(a,r:integer):real;
begin
if(a=1)then
permutasi:=1
else
permutasi:=factorial(a)/factorial(a-r);
end;
var x,y:integer;
begin
writeln('program permutasi');
writeln;
write('Berapa banyak n: ');
readln(x);
write('jumlah yang dipilih(r): ');
readln(y);
writeln;
writeln('permutasi =', permutasi(x,y):3:0);
readln;
end.