// @EXPECTED_RESULTS@: WRONG_ANSWER, TIME_LIMIT_EXCEEDED
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#define MAXN 300005

char s[MAXN];
char done[MAXN];

int main() {
    scanf("%s", s);

    int n = strlen(s);
    int ans = 0;
    int used = 0;
    while (used < n) {
        ++ans;
        int state = 0;
        for (int i = 0; i < n; ++i) {
            if (!done[i]) {
                int x = 1 << (s[i] - 'A');
                if ((state & x) == 0) {
                    ++used;
                    done[i] = 1;
                    state |= x;

                    if (state == 7)
                        state = 0;
                }
            }
        }
    }

    printf("%d\n", ans);
    return 0;
}