#include<iostream>
#include<algorithm>
#include<cstdio>
#include<string.h>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
using namespace std;
//vector学习
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
freopen("in.txt","r",stdin);
map<char,int> ma;
//multiset<char> se;
int n;
char x;
printf("输入n:\n");
cin>>n;
for(int i=0;i<n;i++)
{
cin>>x;
ma[x]=x-'a'+1;
}
printf("是否为空?\n");
cout<<ma.empty()<<endl;
printf("ma的长度:\n");
cout<<ma.size()<<endl;
printf("从头到尾输出元素:\n");
for(map<char,int>::iterator it=ma.begin();it!=ma.end();it++)
cout<<it->first<<' '<<ma[it->first]<<endl;
return 0;
}