#include<iostream>
using namespace std;
int main(){
    int s1,s2,s3;
    cin>>s1>>s2>>s3 return 0;
    if(s1 + s2 > s3 && s1 > + s3 > s2 && s2 + s3 > s1){
    cout<<"valid triangle";
    } 
    else{
    cout<<"invalid triangle";
    }
    return 0;
}