uses crt;
var a,b,c,h:longint;
begin
clrscr;
write('Nhap a: ');readln(a);
write('Nhap b: ');readln(b);
write('Nhap c: ');readln(c);
write('Nhap h: ');readln(h);
if (a+b>c)and(a+c>b)and(b+c>a) then
begin
writeln('Chu vi: ',a+b+c);
writeln('Dien tich: ',(a*h)/2:0:2);
end else writeln('Day khong la tam giac');
readln
end.