#include<iostream> using namespace std; int main(){ int a,b,c; cin>>a>>b>>c; if(a>b&&a>c) swap(a,c); if(b>a&&b>c) swap(b,c);//c最大 if(a+b>c){//合法 if(a*a+b*b>c*c) cout<<"acute triangle"; else if(a*a+b*b==c*c) cout<<"right triangle"; else cout<<"obtuse triangle"; }else cout<<"illegal triangle"; //不合法 return 0; }