nenu contest

#include<cstdio>
typedef __int64 LL;
const int M=1000010;
char a[M][4];
int main(){
int n;
while(~scanf("%d",&n)){
for(int i=0;i<n;i++){
scanf("%s",a[i]);
}
LL ans=0;
LL sum=0;
for(int i=n-1;i>=0;i--){
if(a[i][0]=='W') ans+=sum;
else sum++;
}
printf("%I64d\n",ans);
}
return 0;
}