#include <iostream>
#include <vector>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <complex>
#include <cmath>
#include <map>
#include <set>
#include <string>
#include <queue>
#include <stack>
#include <bitset>
using namespace std;
#define pb(x) push_back(x)
#define ll long long
#define mk(x, y) make_pair(x, y)
#define lson l, m, rt<<1
#define mem(a) memset(a, 0, sizeof(a))
#define rson m+1, r, rt<<1|1
#define mem1(a) memset(a, -1, sizeof(a))
#define mem2(a) memset(a, 0x3f, sizeof(a))
#define rep(i, n, a) for(int i = a; i<n; i++)
#define fi first
#define se second
typedef complex <double> cmx;
typedef pair<int, int> pll;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int mod = 1e9+7;
const int inf = 1061109567;
const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
const int maxn = 1e5+5;
int v[maxn*2], n, b[maxn], cnt, num, sum[maxn*2], ans[maxn];
struct node
{int l, r, id, val;
}a[maxn];
bool cmp1(const node& lhs, const node& rhs)
{return lhs.id < rhs.id;
}
bool cmp2(const node& lhs, const node& rhs)
{if(lhs.r != rhs.r)return lhs.r > rhs.r;if(lhs.l != rhs.l)return lhs.l < rhs.l;return lhs.id < rhs.id;
}
int lowbit(int x) {return x&(-x);}
void update(int x, int val)
{while(x <= cnt) {sum[x] += val;x += lowbit(x);}
}
int query(int x)
{int ret = 0;while(x) {ret += sum[x];x -= lowbit(x);}return ret;
}
void cdq(int l, int r)
{if(l == r) return ;int m = l+r>>1;cdq(l, m);cdq(m+1, r);sort(a+l, a+1+r, cmp2);for(int i = l; i <= r; i++) {if(a[i].id <= m && a[i].val)update(a[i].l, a[i].val);if(a[i].id > m && !a[i].val)ans[a[i].id] += query(a[i].l);}for(int i = l; i <= r; i++)if(a[i].id <= m && a[i].val)update(a[i].l, -a[i].val);}
void solve()
{mem(ans);mem(sum);sort(v, v+cnt);cnt = unique(v, v+cnt)-v;for(int i = 1; i <= n; i++) {a[i].l = lower_bound(v, v+cnt, a[i].l)-v+1;a[i].r = lower_bound(v, v+cnt, a[i].r)-v+1;}cdq(1, n);sort(a+1, a+1+n, cmp1);for(int i = 1; i <= n; i++) {if(!a[i].val)printf("%d\n", ans[i]);}
}
int main()
{int x;while(~scanf("%d", &n)) {cnt = num = 0;for(int i = 1; i <= n; i++) {char ch[1];scanf("%s", ch);a[i].id = i;if(ch[0] == 'C') {scanf("%d", &x);a[i].l = a[b[x]].l;a[i].r = a[b[x]].r;a[i].val = -1;} else {scanf("%d%d", &a[i].l, &a[i].r);v[cnt++] = a[i].l;v[cnt++] = a[i].r;if(ch[0] == 'D') {b[++num] = i;a[i].val = 1;} else {a[i].val = 0;}}}solve();}return 0;
}