include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
include [HTML_REMOVED]
using namespace std;
typedef long long LL;
LL ans=0;
int n;
const int N=5e5+10;
char s[N];
int l[N],r[N];
int main()
{
ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin>>n;
for(int i=1;i<=n;i)
{
cin>>s[i];
}
int h=0,g=0;
for(int i=1;i<=n;i)
{
if(s[i]==’H’)
{
l[i]=g;
g=0;
h;
}
else if(s[i]==’G’)
{
l[i]=h;
h=0;
g;
}
}
g=0,h=0;
for(int i=n;i>=1;i–)
{
if(s[i]==’H’)
{
r[i]=g;
g=0;
h;
}
else if(s[i]==’G’)
{
r[i]=h;
h=0;
g;
}
}
// for(int i=1;i<=n;i++)
// {
// cout<[HTML_REMOVED]1)
{
long long cnt=(long long)l[i]*r[i]+max(0,l[i]-1)+max(0,r[i]-1);
ans+=cnt;
}
}
cout<<ans;
return 0;
}