#include <iostream>
#include <cmath>
#include <iostream>
#include <iterator>
#include <map>
#include <set>
#include <string>
#include <vector>
#include <algorithm>
#include <stack>
#include <deque>
#include <queue>
#include <climits>
#include <cstdio>

#define ll long long
#define db double
#define ff first
#define ss second
#define ll long long

// const int MOD = 1e9 + 7;
const int MOD = 1e9 + 9;
// const int INF = LONG_MAX;
// const int INF = INT_MAX;
const int INF = 10000000;
const int P1 = 179;
// const int P2 = 307;
const int P2 = 257;
 //const int MAXN = 4;
const int MAXN = 1 << 17;


using namespace std;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    freopen("H:\\Downloads\\24 (1)\\24.txt", "r", stdin);
    string s;
    cin >> s;
    int countA = 0;
    int maxLen = 0;
    int len = 0;
    int lenLastF = 0;
    for (int i = 0; i < s.size(); i++) {
        if (len == 0 && s[i] == 'F') {
            len = 1;
        }
        if (len != 0) {
            if (s[i] == 'A') {
                countA++;
                if (countA == 3) {
                    countA = 0;
                    maxLen = max(maxLen, lenLastF);
                    len = 0;
                    lenLastF = 0;
                }
                else {
                    len++;
                }
            }
            if (s[i] == 'F') {
                lenLastF = ++len;
            }
            else {
                len++;
            }
        }
    }
    cout << maxLen;
}