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

int main(void) {
    int n;
    scanf("%d", &n);

    char ch[100005];
    getchar();

    fgets(ch, sizeof(ch), stdin);
    ch[strcspn(ch, "\n")] = '\0';

    int sum = strlen(ch);
    if (n > sum)
        n = sum;

    int count = 0;
    int max = 0;
    for (int i = 0; i < n; i++) {
        if (ch[i] == 'a' || ch[i] == 'h') {
            if (count == 0)
                count = 1;
            else
                if (ch[i] != ch[i - 1])
                    count++;
                else
                    count = 1;
            if (count > max)
                max = count;
        }
        else
            count = 0;
    }

    printf("%d", max);

    return 0;
}