import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String S = scanner.nextLine();
        long L = scanner.nextLong();
        long R = scanner.nextLong();
 
        int n = S.length();
        long countB = 0;
        for (char c : S.toCharArray()) {
            if (c == 'B') {
                countB++;
            }
        }
 
        int[] prefix = new int[n + 1];
        prefix[0] = 0;
        for (int i = 1; i <= n; i++) {
            prefix[i] = prefix[i - 1] + (S.charAt(i - 1) == 'B' ? 1 : 0);
        }
 
        long result = f(R, n, countB, prefix) - f(L - 1, n, countB, prefix);
        System.out.println(result);
    }
 
    private static long f(long i, int n, long countB, int[] prefix) {
        if (i == 0) {
            return 0;
        }
        long k = i / n;
        int r = (int) (i % n);
        return k * countB + prefix[r];
    }
}

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QkJSQgo0IDg=

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4 8