#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<P,int> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
//const ll mod=1e9+7;
const ull mod=998244353;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

const int M=1000005;
int n,q;
ull a[M];

int main(){
	cin>>n>>q;
	ull H=0;
	a[1]=1;
	map<ull,int> m;
	m[0]=0;
	vi b;
	for(int i=2;i<M;i++) a[i]=a[i-1]*mod;
	for(int i=1;i<M;i++) a[i]+=a[i-1];
	for(int i=0;i<q;i++){
		char c;
		cin>>c;
		if(c=='!'){
			ull l,r,k;
			cin>>l>>r>>k;
			H+=(a[r]-a[l])*k;
			if(m.find(H)==m.end()) m[H]=i+1;
		}
		else cout<<m[H]<<endl;
	}
}