dalao帮我康康哪里出问题乐，样例都过了QAQ

#include<bits/stdc++.h>
using namespace std;
int n,ans;
string a,b = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int main(){
	cin>>n;
	for(int i = 0;i<n;i++)
	{
		cin>>a;
		if(a[0] == b[ans])
			ans++;
		a = "";
	}
	cout<<ans<<endl;
	return 0;
}