import java.util.Scanner;

public class CodeForces {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        String s = sc.next();
        
        int ci = 0;
        int ca = 0;
        for(int i=0; i<s.length();i++){
            if(s.charAt(i)=='A'){
                ca++;
            }else if(s.charAt(i)=='I') ci++;
        }
        
        if(ci>0){
            System.out.println(ci);
        }else{
            System.out.println(ca);
        }
    }

}
