#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define X first
#define Y second
#define mins(a, b) (a = min(a,b))
#define SZ(x) int(x.size())
#define lc id<<1
#define rc lc|1
#define mid ((l+r)>>1)
template<typename T> pair<T, T> operator+(pair<T, T> x, pair<T, T> y) {
return pair<T, T>(x.X+y.X, x.Y+y.Y);
}
const int MXN = 3e5+5;
int n;
namespace BG {
int seg[MXN<<2];
void upd(int p, int x, int l=1, int r=n, int id=1) {
if(r-l == 1) {
seg[id] = x;
return;
}
p<mid ? upd(p, x, l, mid, lc) : upd(p, x, mid, r, rc);
seg[id] = max(seg[lc], seg[rc]);
}
int fir(int s, int x, int l=1, int r=n, int id=1) {
if(r<=s || seg[id]<=x) return n;
if(r-l == 1) return l;
int res = fir(s, x, l, mid, lc);
return res==n ? fir(s, x, mid, r, rc) : res;
}
}
namespace LW {
int seg[MXN<<2];
void upd(int p, int x, int l=1, int r=n, int id=1) {
if(r-l == 1) {
seg[id] = x;
return;
}
p<mid ? upd(p, x, l, mid, lc) : upd(p, x, mid, r, rc);
seg[id] = min(seg[lc], seg[rc]);
}
int fir(int s, int x, int l=1, int r=n, int id=1) {
if(r<=s || seg[id]>=x) return n;
if(r-l == 1) return l;
int res = fir(s, x, l, mid, lc);
return res==n ? fir(s, x, mid, r, rc) : res;
}
}
struct node {
pll sl, sr;
pii sg, s1, s2;
bool h2, h3;
} seg[MXN<<2];
inline node leaf(pii sg) {
node z;
z.sl = z.sr = pll(0, 0);
z.sg = z.s1 = sg;
z.h2 = z.h3 = 0;
return z;
}
inline pll merge(ll cur, node y) {
if(cur<y.s1.X) return y.sl + pll(0, y.sg.X-cur);
if(cur>y.s1.Y) return y.sr + pll(cur-y.sg.Y, 0);
if(!y.h2) return pll(0, 0);
if(y.s2.Y<y.s1.X) return y.sr + pll(cur-y.sg.Y, 0);
return y.sl + pll(0, y.sg.X-cur);
}
inline node merge(node x, node y) {
node z;
z.sg = x.sg;
if(!x.h2) {
if(max(x.s1.X, y.s1.X)<=min(x.s1.Y, y.s1.Y)) {
z.s1 = pii(max(x.s1.X, y.s1.X), min(x.s1.Y, y.s1.Y));
z.s2 = y.s2; z.h2 = y.h2;
z.h3 = y.h3;
}
else {
z.s1 = x.s1;
z.s2 = y.s1; z.h2 = 1;
z.h3 = y.h2;
}
}
else if(!x.h3) {
z.s1 = x.s1;
z.h2 = 1;
if(max(x.s2.X, y.s1.X)<=min(x.s2.Y, y.s1.Y)) {
z.s2 = pii(max(x.s2.X, y.s1.X), min(x.s2.Y, y.s1.Y));
z.h3 = y.h2;
}
else {
z.s2 = x.s2;
z.h3 = 1;
}
}
else {
z.s1 = x.s1;
z.s2 = x.s2; z.h2 = x.h2;
z.h3 = x.h3;
}
z.sl = x.sl + merge(x.sg.X - x.sl.X + x.sl.Y, y);
z.sr = x.sr + merge(x.sg.Y - x.sr.X + x.sr.Y, y);
return z;
}
int L[MXN], R[MXN];
void build(int l=1, int r=n, int id=1) {
if(r-l == 1) {
seg[id] = leaf(pii(L[l], R[l]));
return;
}
build(l, mid, lc);
build(mid, r, rc);
seg[id] = merge(seg[lc], seg[rc]);
}
void upd(int p, pii x, int l=1, int r=n, int id=1) {
if(r-l == 1) {
seg[id] = leaf(x);
return;
}
p<mid ? upd(p, x, l, mid, lc) : upd(p, x, mid, r, rc);
seg[id] = merge(seg[lc], seg[rc]);
}
node get(int s, int e, int l=1, int r=n, int id=1) {
if(s<=l && r<=e) return seg[id];
if(e<=mid) return get(s, e, l, mid, lc);
if(s>=mid) return get(s, e, mid, r, rc);
return merge(get(s, e, l, mid, lc), get(s, e, mid, r, rc));
}
int Lin[MXN], Rin[MXN], q;
vector<int> Q[MXN];
ll ans[MXN];
void solve() {
for(int i=1; i<n; i++) {
L[i] = Lin[i]-i;
R[i] = Rin[i]-i-1;
BG::upd(i, L[i]);
LW::upd(i, R[i]);
}
build();
for(int i=1; i<=q; i++)
if(Q[i][0]==1) {
BG::upd(Q[i][1], Q[i][2]-Q[i][1]);
LW::upd(Q[i][1], Q[i][3]-Q[i][1]+1);
upd(Q[i][1], pii(Q[i][2]-Q[i][1], Q[i][3]-Q[i][1]-1));
}
else if(Q[i][1]==Q[i][3]) ans[i] = max(0, Q[i][2]-Q[i][4]);
else if(Q[i][1]<Q[i][3]) {
ll a = Q[i][1], b = Q[i][2]-a, c = Q[i][3], d = Q[i][4]-c;
int pl = BG::fir(a, b), pr = LW::fir(a, b), pos = min(pl, pr);
if(pos>=c) {
ans[i] = max(0ll, b-d);
continue;
}
pll x = pos==pl
? get(pos, c).sl + pll(0, get(pos, pos+1).sg.X - b)
: get(pos, c).sr + pll(b - get(pos, pos+1).sg.Y, 0);
b += x.Y - x.X;
ans[i] = x.X + max(0ll, b-d);
}
}
int32_t main() {
cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
cin >> n >> q;
if(n==1) {
while(q--) {
int t;
cin >> t;
if(t==1) cin >> t >> t >> t;
else {
int b, d;
cin >> t >> b >> t >> d;
cout << max(0, b-d) << '\n';
}
}
return 0;
}
for(int i=1; i<n; i++) cin >> Lin[i] >> Rin[i];
for(int i=1; i<=q; i++) {
int t;
cin >> t;
if(t==1) {
Q[i].resize(4, t);
for(int j=1; j<4; j++) cin >> Q[i][j];
}
else {
Q[i].resize(5, t);
for(int j=1; j<5; j++) cin >> Q[i][j];
}
}
solve();
reverse(Lin+1, Lin+n);
reverse(Rin+1, Rin+n);
for(int i=1; i<=q; i++)
if(Q[i][0]==1)
Q[i][1] = n - Q[i][1];
else
Q[i][1] = n+1 - Q[i][1],
Q[i][3] = n+1 - Q[i][3];
solve();
for(int i=1; i<=q; i++)
if(Q[i][0]==2)
cout << ans[i] << '\n';
return 0;
}
