#include<bits/stdc++.h>
using namespace std;
long long h,zh;
long long n;
string s;
int main()
{
	cin>>n>>s;
	for(int i=0;i<2;i++)
	{
		if(s[i]=='B') h++;
		else if(s[i]=='C') zh++;
	}
	if(zh&&h) cout<<n/10*6;
	else if(zh) cout<<n/10*7;
	else if(h) cout<<n/10*8;
    return 0;
}