#include<bits/stdc++.h>
using namespace std;
using ll = long long;
struct obj{
ll l0,r0,l1,r1,c,m0,m1;
obj(ll a,ll b, ll c, ll d, ll e, ll f, ll g):l0(a),r0(b),l1(c),r1(d),c(e),m0(f),m1(g){}
obj(ll l, ll r):l0(l),r0(r-1),l1(l+1),r1(r),c(0),m0(l),m1(r-1){}
obj():l0(0),r0(0),l1(0),r1(0),c(0),m0(0),m1(0){}
ll cal(ll a, ll b) const{
ll ans = 0;
a = max(a,l0);
if (a>r0){
ans += a-r0;
a = r0;
}
if (l1==r1){
if (a<=m0) ans += c;
else ans += c + a-m0;
if (b<l1) ans += l1-b;
}else{
if (a>=m1) ans += a-m1;
ll ot = max(min(a,m1),m0)-m0+l1;
if (b<ot) ans += ot-b;
}
return ans;
}
obj operator+(const obj &o) const{
if (l1==r1){
if (o.l1==o.r1){
return obj(l0,r0,o.l1,o.r1,c+o.cal(l1+0,o.l1),m0,m1);
}else{
ll ot = max(min(l1+0,o.m1),o.m0)-o.m0+o.l1;
return obj(l0,r0,ot,ot,c+o.cal(l1+0,ot),m0,m1);
}
}else{
if (o.l1==o.r1){
if (o.m0<l1+0){
return obj(l0,r0,o.l1,o.r1,o.c+(l1+0-o.m0),m0,m1);
}else if (o.m0<=r1+0){
ll ot = o.m0-0+m0-l1;
return obj(l0,r0,o.l1,o.r1,o.c,ot,m1);
}else{
return obj(l0,r0,o.l1,o.r1,o.c,m1,m1);
}
}else{
if (r1+0<=o.m0){
return obj(l0,r0,o.l1,o.l1,0,m1,m1);
}else if (l1+0>=o.m1){
return obj(l0,r0,o.r1,o.r1,l1+0-o.m1,m0,m1);
}else{
ll L1,R1,M0,M1;
if (l1+0<=o.m0){
L1 = o.l1;
M0 = m0+o.m0-(l1+0);
}else{
L1 = l1+0-o.m0+o.l1;
M0 = m0;
}
if (r1+0>=o.m1){
R1 = o.r1;
M1 = m1-(r1+0-o.m1);
}else{
R1 = o.r1-(o.m1-(r1+0));
M1 = m1;
}
return obj(l0,r0,L1,R1,0,M0,M1);
}
}
}
}
void out()const{
cout << l0 << " " << r0 << " " << l1 << " " << r1 << " " << c << " " << m0 << " " << m1 << "\n";
}
};
struct segtree{
vector<obj> a;
ll n;
segtree(ll N):n(N),a(N<<2){}
void set(ll i, ll l, ll r, ll x, obj o){
if (l == r) a[i] = o;
else{
ll m = l+r>>1;
if(x<=m) set(i<<1,l,m,x,o);
else set(i<<1|1,m+1,r,x,o);
a[i] = a[i<<1]+a[i<<1|1];
}
}
obj query(ll i, ll l, ll r, ll ql, ll qr){
if (ql<=l&&r<=qr) return a[i];
else{
ll m = l+r>>1;
if (ql<=m&&m<qr) return query(i<<1,l,m,ql,qr)+query(i<<1|1,m+1,r,ql,qr);
else if (ql<=m )return query(i<<1,l,m,ql,qr);
else return query(i<<1|1,m+1,r,ql,qr);
}
}
};
int main(){
ios::sync_with_stdio(0);cin.tie(0);
ll n,q;
cin >> n >> q;
vector<ll> L(n-1),R(n-1);
for(ll i = 0;i<n-1;i++) cin >> L[i] >> R[i];
segtree t0(n-1),t1(n-1);
for(ll i = 0;i<n-1;i++){
t0.set(1,0,n-1,i,obj(L[i],R[i]));
t1.set(1,0,n-1,n-2-i,obj(L[i],R[i]));
}
while(q--){
ll t,a,b,c,d;
cin >> t >> a >> b >> c;a--;
if (t==1){
L[a] = b;
R[a] = c;
t0.set(1,0,n-1,a,obj(b,c));
t1.set(1,0,n-1,n-2-a,obj(b,c));
}else{
c--;
cin >> d;
ll ans = 0;
ll t = b;
ll cur = a;
if (c>a){
obj o = t0.query(1,0,n-1,a,c-1);
//o.out();
ans = o.cal(b,d);
}else if (c<a){
obj o = t1.query(1,0,n-1,(n-2)-(a-1),(n-2)-c);
//o.out();
ans = o.cal(b,d);
}else{
ans = max(0ll,b-d);
}
cout << ans << "\n";
}
}
}
