#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool upmin(T &x, T y) {
  return y < x ? x = y, 1 : 0;
}
template <typename T>
inline bool upmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
const long double eps = 1e-11;
const long double pi = acos(-1);
const int oo = 1 << 30;
const long long loo = 1ll << 62;
const int mods = 998244353;
const int MAXN = 600005;
const int INF = 0x3f3f3f3f;
inline int read() {
  int f = 1, x = 0;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    x = (x << 3) + (x << 1) + (c ^ 48);
    c = getchar();
  }
  return x * f;
}
int a[MAXN];
long long ans = 0;
char st[MAXN];
int main() {
  int n = read();
  scanf("%s", st + 1);
  int cnt = 1, num = 0;
  for (int i = 2; i <= n + 1; i++)
    if (st[i] == st[i - 1])
      cnt++;
    else
      a[++num] = cnt, cnt = 1;
  if (num == 1) {
    printf("%lld\n", 1ll * n * (n - 1) / 2);
    return 0;
  }
  long long ans = a[1] + a[num];
  for (int i = 2; i <= num - 1; i++) ans += a[i] * 2;
  printf("%lld\n", 1ll * n * (n - 1) / 2 - (ans - num + 1));
  return 0;
}
