#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod1 = 9_ten + 7;
constexpr long long mod2 = 9_ten + 9;
constexpr long long mod3 = 1000000021;

#include <tuple>

int main(){
  int n,q;
  cin >> n,q;

  long long p1 = 10007;
  long long p2 = 10009;
  long long p3 = 114514;

  vector<long long> x(n+10, 1);
  vector<long long> y(n+10, 1);
  vector<unsigned long long> z(n+10, 1);
  for(auto i : range(1,n+10) ){
    x[i] = x[i-1] * p1 % mod1;
    y[i] = y[i-1] * p2 % mod2;
    z[i] = z[i-1] * p3 % mod3;
  }

  map<tuple<long long,long long,long long>, int> memo;
  vector<tuple<long long,long long,long long>> hash(q+1);

  memo[hash[0]] = 0;
  for(int i=0; i<q; i++){
    string s;
    cin >> s;

    hash[i+1] = hash[i];

    if(s == "!"){
      int l, r, k;
      cin >> l,r,k;

      l += 5;
      r += 5;

      (get<0>(hash[i+1]) += (mod1+k)%mod1 * (x[r] - x[l] + mod1) % mod1) %= mod1;
      (get<1>(hash[i+1]) += (mod2+k)%mod2 * (y[r] - y[l] + mod2) % mod2) %= mod2;
      (get<2>(hash[i+1]) += (mod3+k)%mod3 * (z[r] - z[l] + mod3) % mod3) %= mod3;

      if(memo.count(hash[i+1]) == 0) memo[ hash[i+1] ] = i+1;
    }else if(s == "?"){
      println(memo[hash[i+1]]);
    }else{
      abort();
    }
  }


  return 0;
}