import javax.swing.*;

public class ProblemE {
	public static void main(String[] args) {
		int i, j, k;
		String S = JOptionPane.showInputDialog("Enter string S");
		
		// Create adjacency matrix
		boolean[][] P;
		P = new boolean[26][];
		for (i = 0; i < 26; ++i)
			P[i] = new boolean[26];
		for (i = 0; i < 26; ++i) {
			for (j = 0; j < 26; ++j) {
				P[i][j] = false;
			}
		}
		k = 0;
		while (k < S.length()) {
			P[S.charAt(k) - 'a'][S.charAt(k+1) - 'a'] = true;
			k += 2;
		}

		// Apply Warshall's Algorithm
		for (k = 0; k < 26; k++) {
			for (i = 0; i < 26; i++) {
				for (j = 0; j < 26; j++) {
					if (! P[i][j]) {
						P[i][j] = P[i][k] && P[k][j];
					}
				}
			}
		}
		
		// Find all concurrent tasks
		int numOfConcurrentTasks = 0;
		for (i = 0; i < 26; ++i) {
			for (j = i+1; j < 26; ++j) {
				if (!P[i][j] && !P[j][i]) {
					numOfConcurrentTasks++;
				}
			}	
		}
		
		// Report answer
		JOptionPane.showMessageDialog(null, "Number of concurrent tasks = " + numOfConcurrentTasks);
	}
}