import java.util.*;
import java.io.*;
import java.lang.*;
//import java.util.Scanner;
//import java.io.InputStream;
//import java.io.IOException;
//import java.util.NoSuchElementException;
//import java.io.PrintWriter;
//import java.lang.Math;
//import java.io.BufferedReader;
//import java.io.InputStreamReader;
//import java.util.StringTokenizer;

public class Main
{
	public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	}
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}

class Util39 {
	public int pow(int a, int b)
	{
		int r = 1;
		for (int i = 0; i < b; i++) r *= a;
		return r;
	}
} import java.util.*; util.* java import java.io.*; io.* java import java.lang.*; lang.* java public class Main
{
	public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	}
} Main public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	} main {
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	} StringBuilder sb = new StringBuilder(); sb new StringBuilder() FastScanner sc = new FastScanner(); sc new FastScanner() Util39 util = new Util39(); util new Util39() String s = sc.next(); s sc.next() sc.next sc char[] c = s.toCharArray(); c s.toCharArray() s.toCharArray s int N = c.length; N c.length c c.length int A = 0; A 0 int Z = N - 1; Z N - 1 N 1 for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		} {
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		} if (c[i] == 'A')
			{
				A = i;
				break;
			} c[i] == 'A' c[i] c i 'A' {
				A = i;
				break;
			} A = i A i break; for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		} int j = Z; int j = Z; j Z j >= 0 j 0 j-- j-- j {
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		} {
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		} if (c[j] == 'Z')
			{
				Z = j;
				break;
			} c[j] == 'Z' c[j] c j 'Z' {
				Z = j;
				break;
			} Z = j Z j break; sb.append(Z - A + 1) sb.append sb Z - A + 1 Z - A Z A 1 PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) out.println(sb.toString()) out.println out sb.toString() sb.toString sb out.flush() out.flush out String[] args args class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
} FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    } hasNextByte {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    } if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        } ptr < buflen ptr buflen {
            return true;
        } return true; true {
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        } ptr = 0 ptr 0 try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                buflen = in.read(buffer);
            } buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
                return false;
            } buflen <= 0 buflen 0 {
                return false;
            } return false; false return true; true private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} readByte { if (hasNextByte()) return buffer[ptr++]; else return -1;} if (hasNextByte()) return buffer[ptr++]; else return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} isPrintableChar { return 33 <= c && c <= 126;} return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} hasNext { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr return hasNextByte(); hasNextByte() hasNextByte public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    } next {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        } isPrintableChar(b) isPrintableChar b {
            sb.appendCodePoint(b);
            b = readByte();
        } sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    } nextLong {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
            minus = true;
            b = readByte();
        } b == '-' b '-' {
            minus = true;
            b = readByte();
        } minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        } b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
            throw new NumberFormatException();
        } throw new NumberFormatException(); new NumberFormatException() while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        } true {
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        } if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            } '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
                n *= 10;
                n += b - '0';
            } n *= 10 n 10 n += b - '0' n b - '0' b '0' if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            } b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
                return minus ? -n : n;
            } return minus ? -n : n; minus ? -n : n minus -n n n {
                throw new NumberFormatException();
            } throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    } nextInt {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    } long nl = nextLong(); nl nextLong() nextLong if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException(); nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE nl < Integer.MIN_VALUE nl Integer.MIN_VALUE Integer Integer.MIN_VALUE nl > Integer.MAX_VALUE nl Integer.MAX_VALUE Integer Integer.MAX_VALUE throw new NumberFormatException(); new NumberFormatException() return (int) nl; (int) nl public double nextDouble() { return Double.parseDouble(next());} nextDouble { return Double.parseDouble(next());} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next class Util39 {
	public int pow(int a, int b)
	{
		int r = 1;
		for (int i = 0; i < b; i++) r *= a;
		return r;
	}
} Util39 public int pow(int a, int b)
	{
		int r = 1;
		for (int i = 0; i < b; i++) r *= a;
		return r;
	} pow {
		int r = 1;
		for (int i = 0; i < b; i++) r *= a;
		return r;
	} int r = 1; r 1 for (int i = 0; i < b; i++) r *= a; int i = 0; int i = 0; i 0 i < b i b i++ i++ i r *= a; r *= a r a return r; r int a a int b b public class Main
{
	public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	}
} public class Main
{
	public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	}
} Main
import java.util.*;
import java.io.*;
import java.lang.*;
//import java.util.Scanner;
//import java.io.InputStream;
//import java.io.IOException;
//import java.util.NoSuchElementException;
//import java.io.PrintWriter;
//import java.lang.Math;
//import java.io.BufferedReader;
//import java.io.InputStreamReader;
//import java.util.StringTokenizer;

public class Main
{
	public static void main(String[] args)
	{
		StringBuilder sb = new StringBuilder();
		
//		Scanner sc = new Scanner(System.in);
		FastScanner sc = new FastScanner();
		Util39 util = new Util39();
//		int n = sc.nextInt();
//		String s = sc.next();
//		int a[] = new int[3];
//		for (int ii = 0; ii < 3; ii++) a[ii] = sc.nextInt();
		
		
		
		String s = sc.next();
		char[] c = s.toCharArray();
		int N = c.length;
		int A = 0;
		int Z = N - 1;

		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'A')
			{
				A = i;
				break;
			}
		}
		for (int j = Z; j >= 0; j--)
		{
			if (c[j] == 'Z')
			{
				Z = j;
				break;
			}
		}
		sb.append(Z - A + 1);
		
		
//		System.out.println(sb.toString());
		PrintWriter out = new PrintWriter(System.out);
		out.println(sb.toString());
		out.flush();
	}
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}

class Util39 {
	public int pow(int a, int b)
	{
		int r = 1;
		for (int i = 0; i < b; i++) r *= a;
		return r;
	}
}
