var
factorial3, factorial2, factorial1 : real;
B, Y, X, i, j, k:byte;
C:real;
begin
write('X = '); readln(X);
write('Y = '); readln(Y);
factorial1 := 1;
factorial2 := 1;
factorial3 := 1;
for i:=2 to x do
begin
factorial1 := factorial1 * i;
end;
for j:=2 to y do
begin
factorial2 := factorial2 * j;
end;
for k:=2 to (x-y) do
begin
factorial3 := factorial3 * k;
end;
C:= ( factorial3 / factorial2 )*factorial1 ;
writeln('C = ',C );
readln;
end.