#include<stdio.h>
int main()
{
int i,k=-1;
char a[100];
while(scanf("%s",&a)!=EOF)
{
int sum=0; for(i=0;a[i]!='\0';i++)
{
if((a[i]=='o'&&a[i+1]=='x')||(a[i]=='o'&&a[i+1]=='\0'))
{
sum+=(1+i-k)*(i-k)/2;
}
if(a[i]=='x'&&a[i+1]=='o')
{
k=i;
}
}
printf("%d\n",sum);
}
}