#include <stdio.h>
#include <string.h>
int main(){
char buf[30];
memset(buf, '\0', sizeof(buf));
int n = 0;
while(~scanf("%d", &n) && n){
fgets(buf, sizeof(buf), stdin);
int sum = 0;
int min = 65535;
for(int i = 0; i < n; ++i){
fgets(buf, sizeof(buf), stdin);//可以直接用不安全的gets(buf);
int len = 0;
char *tmp = buf;
while(*tmp++ == 'X');
--tmp;//就是这个地方忘记回退多走的一步指针,之前就没得到AC
while(*tmp++ == ' '){
++len;
}
if(len < min){
min = len;
}
sum += len;
len = 0;
memset(buf, '\0', sizeof(buf));
}
printf("%d\n", sum - min * n);
}
return 0;
}