code：

#include<iostream>
#include<cstdio>
#include<cctype>
#include<cmath>
#include<algorithm>
using namespace std;
int main()
{
	int a, b, c, a2, b2, c2;
	cin >> a >> b >> c;
	a2 = a * a;
	b2 = b * b;
	c2 = c * c;
	if (a + b < c || a + c < b || b + c < a)
	{
		printf("Not triangle");
		return 0;
	}
	if (a2 + b2 == c2 || a2 + c2 == b2 || c2 + b2 == a2)
		printf("Right triangle\n");
	else if (a2 + b2 > c2 && a2 + c2 > b2 && c2 + b2 > a2)
		printf("Acute triangle\n");
	else if (a2 + b2 < c2 || a2 + c2 < b2 || c2 + b2 < a2)
		printf("Obtuse triangle\n");
	if (a == b || a == c || c == b)
		printf("Isosceles triangle\n");
	if (a == c && a == b)
		printf("Equilateral triangle\n");
	return 0;
}

#6 WA