#include <bits/stdc++.h>
using namespace std;
int main(){
	int n,i,j;
	cin>>n;
	int a[n],s[6]={0};
	char d[6]={'A','B','C','D','E','F'};
	for(i=0;i<n;i++){
		cin>>a[i];
		if(a[i]>59){
			s[0]++;	
		}else if(a[i]>49){
			s[1]++;
		}else if(a[i]>39){
			s[2]++;
		}else if(a[i]>29){
			s[3]++;	
		}else if(a[i]>19){
			s[4]++;	
		}else{
			s[5]++;
		}
	}
	for(j=5;j>0;j--){
		for(i=0;i<j;i++){
			if(s[i]<s[i+1]){
				swap(s[i],s[i+1]);
				swap(d[i],d[i+1]);
			}
		}
	}
	for(i=0;i<6;i++){
		cout<<d[i]<<":"<<s[i]<<endl;
	}
	
}


/**************************************************************
	Problem: 1314
	User: 15159808820
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/