#include <iostream>
#include <string>
using namespace std;
int main(){
    int N,valid=0;
    cin>>N;
    string Code;
    int securityLevel;
    for(int i=0;i<N;i++){
        cin>>Code>>securityLevel;
        if(securityLevel>=50){
            cout<<doorCode<<":"<<securityLevel<<endl;
            valid++;
        }
    }
    if(valid==0)cout<<"No valid doors";
    return 0;
}