#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
// #define int long long
int inf = 2e9;
pair<int,int> a[300001], b[300001];
struct Node{
int ipl, ipr, opl, opr, cost;
};
Node sen = {inf, inf, inf, inf ,inf};
Node tr[1200001], tr2[1200001];
Node merge(Node p, Node q){
Node c;
if(p.ipl==inf)return q;
if(q.ipl==inf)return p;
c = p;
if(p.opr < q.ipl){
c.ipl = c.ipr;
c.opl = q.opl;
c.opr = q.opl;
c.cost += q.cost;
}else if(p.opl > q.ipr){
c.cost += q.cost + (c.opl - q.ipr);
c.ipr = c.ipl;
c.opl = q.opr;
c.opr = q.opr;
}else{
c.cost += q.cost;
int dau = max(p.opl, q.ipl), cuoi = min(p.opr, q.ipr);
c.ipl = p.ipl+(dau-p.opl), c.ipr = p.ipr- (p.opr-cuoi);
c.opl = q.opl + (dau-q.ipl);
c.opr = q.opr - (q.ipr-cuoi);
}
return c;
}
void build(int node, int start, int end){
if(start==end){
tr[node] = {a[start].f, a[start].s, a[start].f, a[start].s, 0};
tr2[node] = {b[start].f, b[start].s, b[start].f, b[start].s, 0};
}else{
int mid = (start+end)/2;
build(2*node, start, mid);
build(2*node+1, mid+1, end);
tr[node] = merge(tr[2*node], tr[2*node+1]);
tr2[node] = merge(tr2[2*node+1], tr2[2*node]);
}
}
void update(int node, int start, int end, int p){
if(start==end){
tr[node] = {a[start].f, a[start].s, a[start].f, a[start].s, 0};
tr2[node] = {b[start].f, b[start].s, b[start].f, b[start].s, 0};
}else{
int mid = (start+end)/2;
if(p<=mid)update(2*node, start, mid, p);
else update(2*node+1, mid+1, end, p);
tr[node] = merge(tr[2*node], tr[2*node+1]);
tr2[node] = merge(tr2[2*node+1], tr2[2*node]);
}
}
Node query(int node, int start, int end, int l, int r){
if(start > r or end<l){
return sen;
}
if(l<=start and end<=r){
return tr[node];
}
int mid = (start+end)/2;
Node t = query(2*node, start, mid, l, r), p =query(2*node+1, mid+1, end, l, r);
return merge(t, p);
}
Node query2(int node, int start, int end, int l, int r){
if(start > r or end<l){
return sen;
}
if(l<=start and end<=r){
return tr2[node];
}
int mid = (start+end)/2;
Node t = query2(2*node, start, mid, l, r), p =query2(2*node+1, mid+1, end, l, r);
return merge(p, t);
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, q;
cin >> n >> q;
for (int i = 1;i<n;++i){
int l, r;
cin >> l >> r;
r--;
a[i] = {l, r};
b[i] = a[i];
a[i].f -= i;
a[i].s -= i;
b[i].f += i;
b[i].s += i;
}
build(1, 1, n-1);
while(q--){
int t, A, B, C, D;
cin >> t >> A >> B >> C;
if(t==1){
C--;
a[A] = {B-A, C-A};
b[A] = {B+A, C+A};
update(1, 1, n-1, A);
}else{
cin >> D;
int sol = 0;
if(A<C){
B-=A;
Node res = query(1, 1, n-1, A, C-1);
// for (int i = 1;i<n;++i){
// cout << a[i].f << ' ' << a[i].s << '\n';
// }
// cout << res.ipl << ' ' << res.ipr << ' ' << res.opl << ' ' << res.opr << ' ' << res.cost << '\n';
// return 0;
sol = res.cost;
if(B >= res.ipr){
sol += B-res.ipr;
}
if(B < res.ipl){
B = res.opl;
}else if(B > res.ipr){
B = res.opr;
}else{
B = res.opl + (B-res.ipl);
}
B += C;
}else if(A>C){
swap(A, C);
B += C-1;
Node res = query2(1,1, n-1, A, C-1);
// for (int i = 1;i<n;++i){
// cout << a[i].f << ' ' << a[i].s << '\n';
// }
// cout << res.ipl << ' ' << res.ipr << ' ' << res.opl << ' ' << res.opr << ' ' << res.cost << '\n';
sol = res.cost;
if(B >= res.ipr){
sol += B-res.ipr;
}
if(B < res.ipl){
B = res.opl;
}else if(B > res.ipr){
B = res.opr;
}else{
B = res.opl + (B-res.ipl);
}
B -= A;
B++;
}
sol += max((int)0, B-D);
cout << sol << '\n';
}
}
}
