#include <bits/stdc++.h>
using namespace std;
long long n, m, a, b, c, d, e, R, B, P, ans;
char s;
inline long long read() {
  long long sum = 0, x = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') x = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    sum = sum * 10 + ch - '0';
    ch = getchar();
  }
  return sum * x;
}
inline void write(long long x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
  return;
}
signed main() {
  n = read();
  for (register long long i = 1; i <= n; ++i) {
    m = read();
    cin >> s;
    if (s == 'P' || s == 'R') {
      if (R) {
        ans += m - b;
        a = max(a, m - b);
      }
      R = 1;
      b = m;
    }
    if (s == 'P' || s == 'B') {
      if (B) {
        ans += m - c;
        d = max(d, m - c);
      }
      B = 1;
      c = m;
    }
    if (s == 'P') {
      if (P) ans += min(0ll, m - e - d - a);
      P = 1;
      a = d = 0;
      e = m;
    }
  }
  write(ans);
  return 0;
}
