import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author nasko
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskB solver = new TaskB();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskB {

    public void solve(int testNumber, InputReader in, PrintWriter out) {

        int n = in.nextInt();

        String s = in.nextLine();

        int A = 0;
        int I = 0;
        int F = 0;
        for(char c : s.toCharArray()) {
            if(c == 'A') ++A;
            if(c == 'I') ++I;
            if(c == 'F') ++F;
        }

        if(I == 0) out.println(A);
        else out.println(I);
    }

}

class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream));
        tokenizer = null;
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(reader.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return tokenizer.nextToken();
    }

    public String nextLine() {
        String s = null;
        try {
            s = reader.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return s;
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

}

