题解

#include<bits/stdc++.h>
using namespace std;
int main(){
    int a;
    cin>>a;
    if(a>770||a<350){
        cout<<"invisible light";
        return 0;
    }
    if(a<=454){
         cout<<"purple";
    }else if(a<=491){
        cout<<"blue"<<endl;
    }else if(a<=576){
        cout<<"green"<<endl;
    }else if(a<=596){
        cout<<"yellow"<<endl;
    }else if(a<=621){    
        cout<<"orange"<<endl; 
    }else if(a<=770){ 
        cout<<"red"<<endl; 
    }
    return 0;
}