
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Random;
import java.util.StringTokenizer;
import java.util.TreeSet;

public class C {

	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		char[] a = sc.next().toCharArray();
		int F = 0, A = 0, I = 0;
		for (int i = 0; i < N; i++)
			if (a[i] == 'F')
				F++;
			else if (a[i] == 'I')
				I++;
			else
				A++;
		int ans = 0;
		if (I == 0 && A > 0) {
			ans = A;
		} else if (I == 1) {
			ans = 1;
		}
		System.out.println(ans);
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

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

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public int[] nextIntArray(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public int[] nextIntArray1(int n) throws IOException {
			int[] a = new int[n + 1];
			for (int i = 1; i <= n; i++)
				a[i] = nextInt();
			return a;
		}

		public int[] nextIntArraySorted(int n) throws IOException {
			int[] a = nextIntArray(n);
			Random r = new Random();
			for (int i = 0; i < n; i++) {
				int j = i + r.nextInt(n - i);
				int t = a[i];
				a[i] = a[j];
				a[j] = t;
			}
			Arrays.sort(a);
			return a;
		}

		public long[] nextLongArray(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public long[] nextLongArray1(int n) throws IOException {
			long[] a = new long[n + 1];
			for (int i = 1; i <= n; i++)
				a[i] = nextLong();
			return a;
		}

		public long[] nextLongArraySorted(int n) throws IOException {
			long[] a = nextLongArray(n);
			Random r = new Random();
			for (int i = 0; i < n; i++) {
				int j = i + r.nextInt(n - i);
				long t = a[i];
				a[i] = a[j];
				a[j] = t;
			}
			Arrays.sort(a);
			return a;
		}
	}
}