#include <cstring>
#include <cmath>
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
int type(char a){
	if(a=='F')
	return 1;
	else if(a=='B')
	return 2;
	else if(a=='I')
	return 3;
	return 0;
	
}
long long  dp[4];
int main(){
	freopen("fbi.in","r",stdin);
	freopen("fbi.out","w",stdout);
	string a;
	cin>>a;
	for(int i=0;i<a.size();i++){
		int d=type(a[i]);
		if(d){
			if(d==1){
				dp[d]++;
			}
			else {
				dp[d]+=dp[d-1];
			}
		}
	}
	cout<<dp[3];
}