#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl
#define svec(v) cout<<#v<<":";rep(pachico,v.size())cout<<" "<<v[pachico];cout<<endl
#define svecp(v) cout<<#v<<":";each(pachico,v)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl
#define sset(s) cout<<#s<<":";each(pachico,s)cout<<" "<<pachico;cout<<endl
#define smap(m) cout<<#m<<":";each(pachico,m)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 1000005;

ll add(ll x,ll y,ll mod)
{
    return (x + y)%mod;
}

ll sub(ll x,ll y,ll mod)
{
    return (x+MOD-y)%mod;
}

ll mul(ll x,ll y,ll mod)
{
    return x*y%mod;
}

map<pll,int> mp;
ll r[2][MAX_N];

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n,q;
    cin >> n >> q;
    ll m[2] = {1009LL,1031LL};
    ll mod[2] = {1000000007LL, 1000000009LL};
    rep(i,2){
        rep(j,n+1){
            r[i][j+1] = mul(r[i][j],m[i],mod[i]);
        }
    }
    ll nw[2] = {0LL,0LL};
    rep(i,q){
        string s;
        cin >> s;
        if(s == "!"){
            int a,b,c;
            cin >> a >> b >> c;
            rep(j,2){
                nw[j] = add(nw[j],mul(r[j][a],(c+mod[j])%mod[j],mod[j]),mod[j]);
                nw[j] = sub(nw[j],mul(r[j][b],(c+mod[j])%mod[j],mod[j]),mod[j]);
            }
            if(mp.find(pll(nw[0],nw[1])) == mp.end()){
                mp[pll(nw[0],nw[1])] = i+1;
            }
        }else{
            cout << mp[pll(nw[0],nw[1])] << "\n";
        }
    }
    return 0;
}