#include<stdio.h>
#include<stdlib.h>
#define MAX_ID 10000
int main(){
    int q;
    scanf("%d", &q);
    int subscribtion[MAX_ID + 1] = {0};
    for(int i = 0; i < q; i++){
        int query_type, id;
        scanf("%d", &query_type);
        if(query_type < 1 || query_type > 4){
            printf("Invalid input\n");
            continue;
        }
        if(query_type == 1 || query_type == 2 || query_type == 3){
            scanf("%d", &id);
            if(id < 1 || id > MAX_ID){
                printf("Invalid input\n");
                continue;
            }
        }
        switch(query_type){
            case 1:
            subscription[id] = 1;
            break;
            case 2;
            subscription[id] == 0;
            break;
            case 3;
            if(subscriptions[id] == 1){
                printf("subscribed\n");
            } else {
                printf("Not subscribed\n");
            }
            break;
            case 4;{
                int count = 0;
                for(int j = 1; j <= MAX_ID; j++){
                    if(subscriptions[j] == 1){
                        count++;
                    }
                }
                printf("%d\n", count);
                break;
            
            }
            default:
            printf("Invalid input\n");
        }
    }
    return 0;
}