#include <cstdio>

#include <map>
#include <set>
#include <vector>
#include <iterator>
#include <algorithm>

using namespace std;

const char iname[] = "zeap.in";
const char oname[] = "zeap.out";

set <int> S;
map <int, int> M;

inline void read(char *p, int &n)
{
	for (; *p < '0' || *p > '9'; ++ p) ;
	for (n = 0; '0' <= *p && *p <= '9'; ++ p)
		n = n * 10 + (*p - '0');
}

int main(void)
{
	FILE *fi, *fo;
	char buffer[16];

	pair <set <int>::iterator, bool> ret;
	set <int>::iterator it, itup, itlow, last;

	int n;

	fi = fopen(iname, "r");
	fo = fopen(oname, "w");

	while (fgets(buffer, 16, fi))
	{
		switch (buffer[0])
		{
			case 'I':
					read(buffer, n);
					if ((ret = S.insert(n)).second == true)
					{
						itup = itlow = ret.first;
						itup ++, itlow --;
							
						if (ret.first != S.begin() && itup != S.end())
						{
							int &tmp = M[*itup - *itlow];
							if ((-- tmp) == 0)
								M.erase(*itup - *itlow);
						}
						if (itup != S.end())
							M[*itup - n] ++;
						if (ret.first != S.begin())
							M[n - *itlow] ++;
					}
				break ;
			case 'S':
					read(buffer, n);
					if ((it = S.find(n)) != S.end())
					{
						itup = itlow = it;
						itup ++, itlow --;

						if (it != S.begin())
						{
							int &tmp = M[n - *itlow];
							if ((-- tmp) == 0)
								M.erase(n - *itlow);
						}
						if (itup != S.end())
						{
							int &tmp = M[*itup - n];
							if ((-- tmp) == 0)
								M.erase(*itup - n);
						}
						if (it != S.begin() && itup != S.end())
							M[*itup - *itlow] ++;
			
						S.erase(it);
					}
					else
						fprintf(fo, "-1\n");
				break ;
			case 'C':
					read(buffer, n);
					fprintf(fo, "%d\n", (S.find(n) != S.end() ? 1 : 0));
				break ;
			case 'M':
					if (S.size() > 1)
						if (buffer[1] == 'A')			
							fprintf(fo, "%d\n", *(-- (last = S.end())) - *S.begin());
						else
							fprintf(fo, "%d\n", (*M.begin()).first);
					else
						fprintf(fo, "-1\n");
				break ;
		}
	}

	fcloseall();

	return 0;
}