Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

type Color struct {
	name    string
	R, G, B int64
}

func main() {
	colors := []Color{
		{"black", 0, 0, 0},
		{"blue", 0, 0, 0xff},
		{"lime", 0, 0xff, 0},
		{"aqua", 0, 0xff, 0xff},
		{"red", 0xff, 0, 0},
		{"fuchsia", 0xff, 0, 0xff},
		{"yellow", 0xff, 0xff, 0},
		{"white", 0xff, 0xff, 0xff},
	}
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), "")
		if buf[0] == "0" {
			break
		}
		r, _ := strconv.ParseInt(strings.Join(buf[1:3], ""), 16, 64)
		g, _ := strconv.ParseInt(strings.Join(buf[3:5], ""), 16, 64)
		b, _ := strconv.ParseInt(strings.Join(buf[5:], ""), 16, 64)
		vmin := int64(3*0xff*0xff)
		var ans string
		for _, c := range colors {
			d := (r-c.R)*(r-c.R) + (g-c.G)*(g-c.G) + (b-c.B)*(b-c.B)
			if d < vmin {
				vmin = d
				ans = c.name
			}
		}
		fmt.Println(ans)
	}
}

C++: #include<iostream>
#include<string>
using namespace std;
string S, x[2][2][2] = { {{"black","blue"}, {"lime","aqua"}}, { {"red","fuchsia"} {"yellow","white"} } };
char T[9] = "89abcdef";
int a, b, c;
int main() {
	while (true) {
		a = 0; b = 0; c = 0;
		cin >> S;
		if (S == "0") { break; }
		for (int i = 0; i < 8; i++){
			if (T[i] == S[1]) {
				a = 1;
			}
		}
		for (int i = 0; i < 8; i++) {
			if (T[i] == S[3]) {
				b = 1;
			}
		}
		for (int i = 0; i < 8; i++) {
			if (T[i] == S[5]) {
				c = 1;
			}
		}
		cout << x[a][b][c] << endl;
	}
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <complex>
#include <cstring>
#include <cstdlib>
#include <string>
#include <cmath>
#include <queue>
using namespace std;

#define REP(i,n) for(int i=0;i<(int)n;++i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define INF 1<<30

int main() {
  string color[] = {"black", "blue", "lime", "aqua", "red", "fuchsia", "yellow", "white"};
  string s;
  while(cin >> s, s!="0") {
    int rgb[3];
    REP(i,3)
      sscanf(s.substr(i*2+1,2).c_str(), "%x", rgb+i);
    int mi = INF;
    int ans;
    REP(i,8) {
      int hoge = 0;
      REP(j,3) {
        if (i<<j & 4)
          hoge += pow(255 - rgb[j], 2);
        else
          hoge += pow(rgb[j], 2);
      }
      if (hoge < mi) {
        mi = hoge;
        ans = i;
      }
    }
    cout << color[ans] << endl;
  }
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <cstring>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <stack>
#include <queue>

using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
static const double EPS = 1e-5;

#define FOR(i,k,n) for (int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n)
int main(void){
  int col;
  char c;
  while(cin>>c>>hex>>col){
    int data[3];
    REP(i,3){
      data[i] = col%256;
      col/=256;
    }
    bool judge[3];
    REP(i,3){
      if(255-data[i]<data[i]){
        judge[i] = false;
      }else{
        judge[i] = true;
      }
    }
    if(judge[0]){
      if(judge[1]){
        if(judge[2]){
          cout<<"black"<<endl;
        }else{
          cout<<"blue"<<endl;
        }
      }else{
        if(judge[2]){
          cout<<"lime"<<endl;
        }else{
          cout<<"aqua"<<endl;
        }
      }
    }else{
      if(judge[1]){
        if(judge[2]){
          cout<<"red"<<endl;
        }else{
          cout<<"fuchsia"<<endl;
        }
      }else{
        if(judge[2]){
          cout<<"yellow"<<endl;
        }else{
          cout<<"white"<<endl;
        }
      }
    }
  }
  return 0;
}

C++: #include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
#include <cassert>
//#include <utility>
//#include <memory>
//#include <functional>
//#include <deque>
//#include <cctype>
//#include <ctime>
//#include <numeric>
//#include <list>
//#include <iomanip>

//#if __cplusplus >= 201103L
//#include <array>
//#include <tuple>
//#include <initializer_list>
//#include <forward_list>
//
//#define cauto const auto&
//#else

//#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif
#define LDcout(x,n) fixed<<setprecision(n)<<x

#define MOD 1000000007LL
#define EPS 1e-8
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define maxs(x,y) x=max(x,y)
#define mins(x,y) x=min(x,y)

int foo(int a,int b,int c){
    int t=a*a+b*b+c*c;
    return t;
}
void mainmain(){
    vector<string> v;
    v.PB("black");
    v.PB("blue");
    v.PB("lime");
    v.PB("aqua");
    v.PB("red");
    v.PB("fuchsia");
    v.PB("yellow");
    v.PB("white");
    string s;
    while(cin>>s){
        if(s.size()==1) return;
        vint w(3,0);
        rep(i,3){
            string tmp=s.substr(1+i*2,2);
            if(isdigit(tmp[0])) w[i]=16*(tmp[0]-'0');
            else{
                w[i]=16*(tmp[0]-'a'+10);
            }
            if(isdigit(tmp[1])) w[i]+=(tmp[1]-'0');
            else{
                w[i]+=(tmp[1]-'a'+10);
            }
        }
        vector<pii> vv(8);
        rep(i,8){
            vint tmp(3);
            rep(j,3){
                if((1<<j)&i) tmp[2-j]=255;
                else tmp[2-j]=0;
            }
            vv[i].S=i;
            vv[i].F=foo(w[0]-tmp[0],w[1]-tmp[1],w[2]-tmp[2]);
        }
        sort(ALL(vv));
        cout<<v[vv[0].S]<<endl;
    }
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
      cout<<fixed<<setprecision(20);
    mainmain();
}

C++: #include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
using namespace std;
typedef long long ll;
int to_int(string s){
	int k=1,res=0;
	for(int i=s.size()-1;i>=0;i--){
		if('0'<=s[i]&&s[i]<='9'){
			res+=k*(s[i]-'0');
		}else{
			res+=k*(s[i]-'a'+10);
		}
		k*=16;
	}
	return res;
}

int main(){
	string ans[2][2][2];
	ans[0][0][0]="black";
	ans[0][0][1]="blue";
	ans[0][1][0]="lime";
	ans[0][1][1]="aqua";
	ans[1][0][0]="red";
	ans[1][0][1]="fuchsia";
	ans[1][1][0]="yellow";
	ans[1][1][1]="white";
	string s;
	while(cin>>s&&s[0]!='0'){
		int a,b,c,dat[3];
		for(int i=1;i<6;i+=2){
			string tmp;int ans[3];
			tmp.assign(s,i,2);
			int d=to_int(tmp);
			if(d<=(to_int("ff")-d))ans[i/2]=0;
			else ans[i/2]=1;
		}
		cout<<ans[dat[0]][dat[1]][dat[2]]<<endl;
	}
}