#include <bits/stdc++.h>

using namespace std;
const int maxn = 50005;
int st[maxn << 2], lz[maxn << 2];
void update(int id, int l, int r, int u, int v, int val) {
    if (v < l || r < u) return;
    if (u <= l && r <= v) {
        lz[id] += val;
        return;
    }
    int mid = (l + r) >> 1;
    update(id << 1, l, mid, u, v, val);
    update(id << 1 | 1, mid + 1, r, u, v, val);
    st[id] = max(st[id << 1] + lz[id << 1], st[id << 1 | 1] + lz[id << 1 | 1]);
}
int get(int id, int l, int r, int u, int v) {
    if (v < l || r < u) return -1e9;
    if (u <= l && r <= v)
        return st[id] + lz[id];
    int mid = (l + r) >> 1;
    return max(get(id << 1, l, mid, u, v),
        get(id << 1 | 1, mid + 1, r, u, v)) + lz[id];
}
int main() {
#ifdef LDT
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int typ;
        cin >> typ;
        if (typ == 0) {
            int x, y, val;
            cin >> x >> y >> val;
            update(1, 1, n, x, y, val);
        }
        else {
            int x, y;
            cin >> x >> y;
            cout << get(1, 1, n, x, y) << '\n';
        }
    }
    return 0;
}