program tamgiac;
uses crt;
var a,b,c: integer;
BEGIN
clrscr;
reapeat begin write ('nhap a = '); readln (a); end;
until a>0;
reapeat begin write ('nhap b = '); readln (b); end;
until b>0;
reapeat begin write ('nhap c = '); readln (c); end;
until c>0;
if (a*a=b*b+c*c) or (b*b=a*a+c*c) or (c*c=a*a+b*b)
then write ('3 canh ay la 3 canh cua tam giac vuong')
else ('3 canh ay khong la 3 canh cua tam giac vuong');
READLN
END.