#include    <stdio.h>

int main(void)
{
    char    c;
    int     n, max, lf;

    lf = 0;
    max = 0;
    n = 0;
    while ((c = getchar()) != EOF) {
        switch (c) {
          case 'x':
            max = n > max ? n : max;
            n = 0;
            break;
          case 'o':
            n++;
            break;
          case '\n':
            lf++;
            break;
          default:
            break;
        }
        if (lf >= 2) {
            max = n > max ? n : max;
            break;
        }
    }

    printf("%d\n", max);

    return 0;
}