import java.lang.*;
import java.io.*;
import java.util.*;


public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
}

class TaskA {
	
	
	public void solve(InputReader in, PrintWriter out) {
		String s = in.next();
		int len = s.length();
		int posa = -1, posz = 0;
		
		for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		}
		
		int ans = posz - posa + 1;
		out.println(ans);
	}
}

class InputReader {
	public BufferedReader reader;
	public StringTokenizer tokenizer;
	
	
	public InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream), 32768);
		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 int nextInt() {
		return Integer.parseInt(next());
	}
	
	public long nextLong() {
		return Long.parseLong(next());
	}
	
	public double nextDouble() {
		return Double.parseDouble(next());
	}
} import java.lang.*; lang.* java import java.io.*; io.* java import java.util.*; util.* java public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
} Main public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	} main {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	} InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskA solver = new TaskA(); solver new TaskA() solver.solve(in, out) solver.solve solver in out out.close() out.close out String[] args args class TaskA {
	
	
	public void solve(InputReader in, PrintWriter out) {
		String s = in.next();
		int len = s.length();
		int posa = -1, posz = 0;
		
		for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		}
		
		int ans = posz - posa + 1;
		out.println(ans);
	}
} TaskA public void solve(InputReader in, PrintWriter out) {
		String s = in.next();
		int len = s.length();
		int posa = -1, posz = 0;
		
		for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		}
		
		int ans = posz - posa + 1;
		out.println(ans);
	} solve {
		String s = in.next();
		int len = s.length();
		int posa = -1, posz = 0;
		
		for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		}
		
		int ans = posz - posa + 1;
		out.println(ans);
	} String s = in.next(); s in.next() in.next in int len = s.length(); len s.length() s.length s int posa = -1 posa -1 1 posz = 0; posz 0 for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		} int i=0; int i=0; i 0 i<len i len ++i ++i i {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		} {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		} if (posa<0 && s.charAt(i)=='A')
				posa = i; posa<0 && s.charAt(i)=='A' posa<0 posa 0 s.charAt(i)=='A' s.charAt(i) s.charAt s i 'A' posa = i posa i if (s.charAt(i) == 'Z')
				posz = i; s.charAt(i) == 'Z' s.charAt(i) s.charAt s i 'Z' posz = i posz i int ans = posz - posa + 1; ans posz - posa + 1 posz - posa posz posa 1 out.println(ans) out.println out ans InputReader in in PrintWriter out out class InputReader {
	public BufferedReader reader;
	public StringTokenizer tokenizer;
	
	
	public InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream), 32768);
		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 int nextInt() {
		return Integer.parseInt(next());
	}
	
	public long nextLong() {
		return Long.parseLong(next());
	}
	
	public double nextDouble() {
		return Double.parseDouble(next());
	}
} InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream), 32768);
		tokenizer = null;
	} InputReader {
		reader = new BufferedReader(new InputStreamReader(stream), 32768);
		tokenizer = null;
	} reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
		while (tokenizer==null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	} next {
		while (tokenizer==null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}
		return tokenizer.nextToken();
	} while (tokenizer==null || !tokenizer.hasMoreTokens()) {
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		} tokenizer==null || !tokenizer.hasMoreTokens() tokenizer==null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
			try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		} try {
				tokenizer = new StringTokenizer(reader.readLine());
			} catch (IOException e) {
				throw new RuntimeException(e);
			} catch (IOException e) {
				throw new RuntimeException(e);
			} IOException e {
				throw new RuntimeException(e);
			} throw new RuntimeException(e); new RuntimeException(e) {
				tokenizer = new StringTokenizer(reader.readLine());
			} tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public int nextInt() {
		return Integer.parseInt(next());
	} nextInt {
		return Integer.parseInt(next());
	} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public long nextLong() {
		return Long.parseLong(next());
	} nextLong {
		return Long.parseLong(next());
	} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public double nextDouble() {
		return Double.parseDouble(next());
	} nextDouble {
		return Double.parseDouble(next());
	} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
} public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
} Main
import java.lang.*;
import java.io.*;
import java.util.*;


public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
}

class TaskA {
	
	
	public void solve(InputReader in, PrintWriter out) {
		String s = in.next();
		int len = s.length();
		int posa = -1, posz = 0;
		
		for (int i=0; i<len; ++i) {
			if (posa<0 && s.charAt(i)=='A')
				posa = i;
			if (s.charAt(i) == 'Z')
				posz = i;
		}
		
		int ans = posz - posa + 1;
		out.println(ans);
	}
}

class InputReader {
	public BufferedReader reader;
	public StringTokenizer tokenizer;
	
	
	public InputReader(InputStream stream) {
		reader = new BufferedReader(new InputStreamReader(stream), 32768);
		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 int nextInt() {
		return Integer.parseInt(next());
	}
	
	public long nextLong() {
		return Long.parseLong(next());
	}
	
	public double nextDouble() {
		return Double.parseDouble(next());
	}
}
