#include <bits/stdc++.h>
#pragma GCC optimize ("O2,unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;
const int inf=1000000010;
const ll INF=1000000000000001000LL;
const int mod=1000000007;
const int MAXN=300010, LOG=20;
int n, m, k, u, v, x, y, t, l, r, a, b, ans;
int A[MAXN];
struct Node{
ll dp[2][2];
Node(ll l=0, ll r=0){
dp[0][0]=l;
dp[0][1]=0;
dp[1][0]=0;
dp[1][1]=-r;
}
};
Node Merge(Node X, Node Y){
Node Z;
for (int a=0; a<2; a++) for (int b=0; b<2; b++)
Z.dp[a][b]=max(X.dp[a][0]+Y.dp[1][b], X.dp[a][1]+Y.dp[0][b]);
return Z;
}
struct Solver{
int L[MAXN], R[MAXN];
Node seg[MAXN<<2];
Solver(){
seg[0].dp[0][0]=-INF;
seg[0].dp[0][1]=0;
seg[0].dp[1][0]=0;
seg[0].dp[1][1]=-INF;
}
void Build(int id, int tl, int tr){
if (tr-tl==1){/*
seg[id].dp[0][0]=L[tl];
seg[id].dp[0][1]=0;
seg[id].dp[1][0]=0;
seg[id].dp[1][1]=-R[tl];*/
seg[id]=Node(L[tl], R[tl]);
return ;
}
int mid=(tl+tr)>>1;
Build(id<<1, tl, mid);
Build(id<<1 | 1, mid, tr);
seg[id]=Merge(seg[id<<1], seg[id<<1 | 1]);
}
void Set(int id, int tl, int tr, int pos){
if (pos<tl || tr<=pos) return ;
if (tr-tl==1){
seg[id].dp[0][0]=L[tl];
seg[id].dp[0][1]=0;
seg[id].dp[1][0]=0;
seg[id].dp[1][1]=-R[tl];
return ;
}
int mid=(tl+tr)>>1;
Set(id<<1, tl, mid, pos);
Set(id<<1 | 1, mid, tr, pos);
seg[id]=Merge(seg[id<<1], seg[id<<1 | 1]);
}
Node Get(int id, int tl, int tr, int l, int r){
if (r<=tl || tr<=l) return seg[0];
if (l<=tl && tr<=r) return seg[id];
int mid=(tl+tr)>>1;
return Merge(Get(id<<1, tl, mid, l, r), Get(id<<1 | 1, mid, tr, l, r));
}
ll Solve(int x, int y, int a, int b){
a-=x;
b-=y;
Node X(a, a);
Node Y=Get(1, 1, n, x, y);
Node Z(b, b);
X=Merge(X, Merge(Y, Z));
// return max(X.dp[0][1], X.dp[1][0]);
return X.dp[0][1];
}
} S1, S2;
void print(Node X){
cerr<<X.dp[0][0]<<" "<<X.dp[0][1]<<"\n";
cerr<<X.dp[1][0]<<" "<<X.dp[1][1]<<"\n";
cerr<<"\n";
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
cin>>n>>m;
for (int i=1; i<n; i++){
cin>>l>>r; r--;
S1.L[i]=l-i;
S2.L[n-i]=l-(n-i);
S1.R[i]=r-i;
S2.R[n-i]=r-(n-i);
}
S1.Build(1, 1, n);
S2.Build(1, 1, n);
/*
debug(S1.seg[1].dp[0][1])
debug(S1.seg[1].dp[1][0])
print(S1.seg[1]);
print(Merge(Node(2, 2), S1.seg[1]));
print(Merge(S1.seg[1], Node(5, 5)));
print(Merge(Merge(Node(2, 2), S1.seg[1]), Node(5, 5)));
*/
while (m--){
cin>>t;
if (t==1){
cin>>x>>l>>r;
r--;
S1.L[x]=l-x;
S2.L[n-x]=l-(n-x);
S1.R[x]=r-x;
S2.R[n-x]=r-(n-x);
S1.Set(1, 1, n, x);
S2.Set(1, 1, n, n-x);
}
else{
cin>>x>>a>>y>>b;
if (x<y) cout<<S1.Solve(x, y, a, b)<<"\n";
else cout<<S2.Solve(n+1-x, n+1-y, a, b)<<"\n";
}
}
return 0;
}
/*
5 1
3 5
4 8
2 6
5 10
2 5 3 1 10
5 1
5 10
2 6
4 8
3 5
2 1 3 5 10
*/
