#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
#define fi first
#define se second
#define MP make_pair

int read() {
    int v = 0, f = 1;
    char c = getchar();
    while (c < 48 || 57 < c) {if (c == '-') f = -1; c = getchar();}
    while (48 <= c && c <= 57) v = (v << 3) + v + v + c - 48, c = getchar();
    return v * f;
}

const int N = 1000000;
int q, cnt;
char op[10];
char ch[32];
int now, n;
int flg[N], A[100];
struct EG {
    int a, b, c;
} eg[N];
int head[N], en;
void SetEdge(int u, int v, int w) {
    eg[++en] = (EG) {v, head[u], w};
    head[u] = en;
}
int find(int u, int c) {
    for (int e = head[u]; e; e = eg[e].b)
        if (eg[e].c == c) return eg[e].a;
    return 0;
}
int main() {
    scanf("%d", &q);
    cnt = 1;
    while (q--) {
        scanf("%s", op);
        memset(ch, 0, sizeof ch);
        scanf("%s", ch + 1);
        n = strlen(ch + 1);
        if (op[0] == 'i') {
            now = 1;
            for (int i = 1; i <= n; i++) {
                if (find(now, ch[i] - 'a') == 0)
                    SetEdge(now, ++cnt, ch[i] - 'a');
                now = find(now, ch[i] - 'a');
                if (!flg[now])
                    for (int e = head[now]; e; e = eg[e].b)
                        flg[eg[e].a] = 0;
                flg[now] = 1;
            }
        }
        if (op[0] == 'd') {
            now = 1;
            A[0] = 0;
            for (int i = 1; i <= n; i++) {
                now = find(now, ch[i] - 'a');
                A[++A[0]] = now;
                if (!flg[now])
                    for (int e = head[now]; e; e = eg[e].b)
                        flg[eg[e].a] = 0;
            }
            flg[now] = 0;
            if (now > 0) {
                for (int i = A[0] - 1; i >= 1; i--) {
                    bool fg = 0;
                    for (int e = head[A[i]]; e; e = eg[e].b) {
                        int v = eg[e].a;
                        if (flg[v]) fg = 1;
                    }
                    flg[A[i]] = fg;
                }
            }
        }
        if (op[0] == 's') {
            now = 1;
            for (int i = 1; i <= n; i++) {
                now = find(now, ch[i] - 'a');
                if (!flg[now])
                    for (int e = head[now]; e; e = eg[e].b)
                        flg[eg[e].a] = 0;
            }
            if (flg[now])
                puts("Yes");
            else
                puts("No");
        }
    }
}