import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

public class Main {
	private static final int MOD = (int)Math.pow(10, 9);
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	}
	
	static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.HashMap; HashMap java.util import java.util.List; List java.util import java.util.Map; Map java.util import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	private static final int MOD = (int)Math.pow(10, 9);
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	}
	
	static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  }
} Main private static final int MOD = (int)Math.pow(10, 9); MOD (int)Math.pow(10, 9) Math.pow Math 10 9 public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	} main {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	} FastReader sc = new FastReader(); sc new FastReader() String s = sc.next(); s sc.next() sc.next sc int idx1 = -1; idx1 -1 1 int idx2 = -1; idx2 -1 1 for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		} int i = 0; int i = 0; i 0 i < s.length() i s.length() s.length s i++ i++ i {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		} {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		} char c = s.charAt(i); c s.charAt(i) s.charAt s i if (c == 'A') {
				idx1 = i;
				break;
			} c == 'A' c 'A' {
				idx1 = i;
				break;
			} idx1 = i idx1 i break; for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		} int i = s.length() - 1; int i = s.length() - 1; i s.length() - 1 s.length() s.length s 1 i >= 0 i 0 i-- i-- i {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		} {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		} char c = s.charAt(i); c s.charAt(i) s.charAt s i if (c == 'Z') {
				idx2 = i;
				break;
			} c == 'Z' c 'Z' {
				idx2 = i;
				break;
			} idx2 = i idx2 i break; System.out.println(idx2 - idx1 + 1) System.out.println System.out System System.out idx2 - idx1 + 1 idx2 - idx1 idx2 idx1 1 String[] args args static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    } FastReader {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    } next { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    } while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      } try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        } catch (IOException  e) {
	          e.printStackTrace();
	        } IOException  e {
	          e.printStackTrace();
	        } e.printStackTrace() e.printStackTrace e {
	          st = new StringTokenizer(br.readLine());
	        } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
	      return Integer.parseInt(next());
	    } nextInt {
	      return Integer.parseInt(next());
	    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
	      return Long.parseLong(next());
	    } nextLong {
	      return Long.parseLong(next());
	    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() { 
	      return Double.parseDouble(next());
	    } nextDouble { 
	      return Double.parseDouble(next());
	    } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      } nextLine {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      } String str = ""; str "" try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        } catch (IOException e) {
	            e.printStackTrace();
	        } IOException e {
	            e.printStackTrace();
	        } e.printStackTrace() e.printStackTrace e {
	            str = br.readLine();
	        } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
	private static final int MOD = (int)Math.pow(10, 9);
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	}
	
	static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  }
} public class Main {
	private static final int MOD = (int)Math.pow(10, 9);
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	}
	
	static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

public class Main {
	private static final int MOD = (int)Math.pow(10, 9);
	public static void main(String[] args) {
		FastReader sc = new FastReader();
		String s = sc.next();
		int idx1 = -1;
		int idx2 = -1;
		
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (c == 'A') {
				idx1 = i;
				break;
			}
		}
		
		for (int i = s.length() - 1; i >= 0; i--) {
			char c = s.charAt(i);
			if (c == 'Z') {
				idx2 = i;
				break;
			}
		}
		System.out.println(idx2 - idx1 + 1);
	}
	
	static class FastReader {
	    BufferedReader br;
	    StringTokenizer st;
	
	    public FastReader() {
	      br = new BufferedReader(new InputStreamReader(System.in));
	    }
	  
	    String next() { 
	      while (st == null || !st.hasMoreElements()) {
	        try {
	          st = new StringTokenizer(br.readLine());
	        } catch (IOException  e) {
	          e.printStackTrace();
	        }
	      }
	      return st.nextToken();
	    }
	
	    int nextInt() {
	      return Integer.parseInt(next());
	    }
	
	    long nextLong() {
	      return Long.parseLong(next());
	    }
	
	    double nextDouble() { 
	      return Double.parseDouble(next());
	    }
	
	    String nextLine() {
	      String str = "";
	        try{
	            str = br.readLine();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }
	        return str;
	      }
	  }
}
