#include<bits/stdc++.h>
using namespace std;
//#define int long long
#define ll long long
const int N = 3e5 + 10;
int n, q;
array<ll,6> tree1[4*N], tree2[4*N], ans, tmp;
pair<int,int> inps[N];
void upd(array<ll,6> &v,array<ll,6> &u1,array<ll,6> &u2) {
if (u1[0] && u2[0]) {
if (min(u1[2],u2[2]) >= max(u1[1],u2[1])) {
v[0] = 1;
v[1] = max(u1[1],u2[1]);
v[2] = min(u1[2],u2[2]);
} else {
v[0] = 0;
if (u1[1] > u2[2]) {
v[3] = u1[1]-u2[2];
v[4] = u1[1];
v[5] = u2[2];
} else {
v[3] = 0;
v[4] = u1[2];
v[5] = u2[1];
}
}
}
if (u1[0] && !u2[0]) {
v[0] = 0;
v[5] = u2[5];
v[3] = u2[3]+max(0ll,u1[1]-u2[4]);
v[4] = max(u1[1],min(u1[2],u2[4]));
}
if (!u1[0] && u2[0]) {
v = u1;
if (u1[5] > u2[2]) {
v[5] = u2[2];
v[3] += u1[5] - u2[2];
} else if (u1[5] < u2[1]) {
v[5] = u2[1];
}
}
if (!u1[0] && !u2[0]) {
v = u1;
v[5] = u2[5];
v[3] += u2[3]+max(0ll,u1[5]-u2[4]);
}
}
void build(int v,int tl,int tr) {
if (tl == tr) {
tree1[v][0] = 1;
tree1[v][1] = inps[tl].first-tl;
tree1[v][2] = inps[tl].second-tl-1;
tree2[v][0] = 1;
tree2[v][1] = inps[tl].first-(n-tl);
tree2[v][2] = inps[tl].second-(n-tl)-1;
return;
}
int mid = (tl+tr)/2;
build(2*v,tl,mid);
build(2*v+1,mid+1,tr);
upd(tree1[v],tree1[2*v],tree1[2*v+1]);
upd(tree2[v],tree2[2*v+1],tree2[2*v]);
}
void change(int v,int tl,int tr,int ind) {
if (ind > tr || ind < tl) return;
if (tl == tr) {
tree1[v][0] = 1;
tree1[v][1] = inps[tl].first-tl;
tree1[v][2] = inps[tl].second-tl-1;
tree2[v][0] = 1;
tree2[v][1] = inps[tl].first-(n-tl);
tree2[v][2] = inps[tl].second-(n-tl)-1;
return;
}
int mid = (tl+tr)/2;
change(2*v,tl,mid,ind);
change(2*v+1,mid+1,tr,ind);
upd(tree1[v],tree1[2*v],tree1[2*v+1]);
upd(tree2[v],tree2[2*v+1],tree2[2*v]);
}
void GET(int v,int tl,int tr,int l,int r,int id) {
if (r < l) return;
if (tl == l && tr == r) {
tmp = ans;
if (id == 1) {
upd(ans,tmp,tree1[v]);
} else {
upd(ans,tmp,tree2[v]);
}
return;
}
int mid = (tl+tr)/2;
if (id == 1) {
GET(2*v,tl,mid,l,min(r,mid),id);
GET(2*v+1,mid+1,tr,max(l,mid+1),r,id);
} else {
GET(2*v+1,mid+1,tr,max(l,mid+1),r,id);
GET(2*v,tl,mid,l,min(r,mid),id);
}
}
/*
5 5
3 5
4 8
2 6
5 10
2 5 3 1 10
2 2 6 5 6
1 3 4 6
2 3 3 4 3
2 4 5 1 5
*/
void solve() {
cin >> n >> q;
for (int i = 1;i <= n-1;i++) {
cin >> inps[i].first >> inps[i].second;
}
build(1,1,n-1);
for (int i = 0;i < q;i++) {
int t;
cin >> t;
if (t == 1) {
int p, s, e;
cin >> p >> s >> e;
inps[p] = {s,e};
change(1,1,n-1,p);
} else {
int a, b, c, d;
cin >> a >> b >> c >> d;
if (a == c) {
cout << max(0,b-d) << '\n';
continue;
}
ans[0] = 1;
ans[1] = -21e8;
ans[2] = 21e8;
if (a < c) {
b -= a;
d -= c;
GET(1,1,n-1,a,c-1,1);
} else {
b -= (n-a+1);
d -= (n-c+1);
GET(1,1,n-1,c,a-1,2);
}
//cout << "a,b,c,d = " << a << ' ' << b << ' ' << c << ' ' << d << '\n';
//cout << "ans[0],l,r,x,st,out = " << ans[0] << ' ' << ans[1] << ' ' << ans[2] << ' ' << ans[3] << ' ' << ans[4] << ' ' << ans[5] << '\n';
ll cost = 0, loc;
if (ans[0]) {
cost = max(0ll,b-ans[2]);
loc = b;
if (loc < ans[1]) loc = ans[1];
if (loc > ans[2]) loc = ans[2];
} else {
cost = ans[3]+max(0ll,b-ans[4]);
loc = ans[5];
}
cout << cost + max(0ll,loc-d) << '\n';
}
}
}
/*
5 1
3 5
4 8
2 6
5 10
2 5 3 1 10
*/
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
}
