#include <stdio.h>
#include <stdlib.h>

int main(void) {
    char m;
    int a = 0, amax = 0;

    for (int i = 0; i < 16; i++) {
        m = getchar();
        if (m == 'o') {a++;}
        else if (m == 'x') {a = 0;}
        if (amax < a) {amax = a;}
    }
    printf("%d", amax);

    return EXIT_SUCCESS;
}