#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a[3]={0};
	for(int i=0;i<3;i++)
	{
		cin>>a[i];
	}
	sort(a,a+3);
	
	int l1=a[0],l2=a[1],l3=a[2];
	
	if(l1+l2<=l3)
	{
		cout<<"Not a triangle!\n";
		return 0;
    }
    if(l1==l2&&l2==l3)
	{
		cout<<"Equilateral triangle!\n";
        return 0;
	}
	if(l1==l2||l2==l3)
	{
		cout<<"Isosceles triangle!\n";
        return 0;
	}
    cout<<"Ordinary triangle!\n";
}

就,这道题注意等边三角形的判断要在等腰三角形之前就行!