#include <stdio.h>
#include <string.h>

int main() {
    char s[101];
    scanf("%s", s);
    int len = strlen(s);

    for (int i = 0; i <= len - 3; i++) {
        if ((s[i] == 'B' || s[i] == 'b') &&
                (s[i + 1] == 'o' || s[i + 1] == 'O') &&
                (s[i + 2] == 'b' || s[i + 2] == 'B')) {
            printf("%d", i);
            return 0;
        }
    }

    printf("-1");
    return 0;
}