#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
int main(void)
{
    int maxholiday=0,holidaycnt=0;
    char input;
    for(int i=0;i<14;i++)
    {
        scanf("%c\n",&input);
        if(input=='x')
        {
            if(maxholiday<holidaycnt)
            {
                maxholiday=holidaycnt;
            }
            holidaycnt=0;
        }
        else
        {
            holidaycnt++;
        }
    }
    if(maxholiday<holidaycnt)
    {
        maxholiday=holidaycnt;
    }
    printf("%d",maxholiday);
}