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

int main(void){
    int i, cnt = 0, maxcnt = 0;
    char c;
    for(i=0;i<=14;i++){
        scanf("%c", &c);
        if(c=='o'){
            cnt++;
        }else if(c=='x'){
            if(cnt>maxcnt){
                maxcnt = cnt;
            }
            cnt = 0;
        }
    }
    if(cnt>maxcnt){
        maxcnt = cnt;
    }
    printf("%d\n", maxcnt);
    return 0;
}