#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b,c;
	cin>>a>>b>>c;
	//排序
	if(a>c)swap(a,c);
	if(b>c)swap(b,c);
	if(a>b)swap(a,b);
	if(a+b<=c){cout<<"Not triangle";return 0;}
	if(pow(a,2)+pow(b,2)==pow(c,2))cout<<"Right triangle"<<endl;
	if(pow(a,2)+pow(b,2)>pow(c,2))cout<<"Acute triangle"<<endl;
	if(pow(a,2)+pow(b,2)<pow(c,2))cout<<"Obtuse triangle"<<endl;
	if(a==b||a==c||b==c)cout<<"Isosceles triangle"<<endl;
	if(a==b&&b==c)cout<<"Equilateral triangle"<<endl;
	return 0;
}

#include<stdio.h>
int main(){
    int a,b,c;
    scanf("%d %d %d",&a,&b,&c);
    if(a+b<=c||a+c<=b||b+c<=a){
        printf("Not triangle\n");
    }
    if(a+b>c&&a+c>b&&b+c>a){
        if(a*a+b*b==c*c||a*a+c*c==b*b||b*b+c*c==a*a){
            printf("Right triangle\n");
        }
        if(a*a+b*b>c*c&&a*a+c*c>b*b&&c*c+b*b>a*a){
            printf("Acute triangle\n");
        }
        if(a*a+b*b<c*c||a*a+c*c<b*b||b*b+c*c<a*a){
            printf("Obtuse triangle\n");
        }
        if(a==b||a==c||c==b){
            printf("Isosceles triangle\n");
        }
        if(a==b&&b==c){
            printf("Equilateral triangle\n");
        }
    }
    return 0;
}

注意exit()或用else，比如1 3 4不能构成三角形，但不加可能被误判为钝角三角形

from math import sqrt,ceil,gcd,log;re=lambda:map(int,input().split())
a = list(re())
a.sort()
if a[0] + a[1] <= a[2]:
    print("Not triangle")
    exit()
if a[0] ** 2 + a[1] ** 2 == a[2] ** 2:
    print("Right triangle")
if a[0] ** 2 + a[1] ** 2 > a[2] ** 2:
    print("Acute triangle")
if a[0] ** 2 + a[1] ** 2 < a[2] ** 2:
    print("Obtuse triangle")
if a[0] == a[1] or a[1] == a[2]:
    print("Isosceles triangle")
if a[0] == a[1] == a[2]:
    print("Equilateral triangle")

#include<stdio.h> int main() { int a,b,c,t; scanf("%d %d %d",&a,&b,&c); if(a>b){ t=b; b=a; b=t; } if(a>c){ t=c; c=a; a=t; } if(b>c){ t=c; c=b; b=t; } if(a0||b0||c0||a+b<=c ||b+c<=a || a+c<=b){ printf("Not triangle"); }else if(aa+bbcc){ printf("Right triangle\n"); if(a==b){ printf("Isosceles triangle"); } }else if(aa+bb>cc){ printf("Acute triangle\n"); if(ab){ printf("Isosceles triangle\n"); if(ac){ printf("Equilateral triangle"); } }

}
	else if(a*a+b*b<c*c){
		printf("Obtuse triangle\n");
		if(a==b){
			printf("Isosceles triangle");
		}
	}
	return 0;

}