#include<cstdio>
#include<algorithm>
#include<vector>
#define SZ 1048576
#define N_ 601000
using namespace std;
const int INF = 2e9;
struct AA {
struct Tree {
long long M, L, R, LR;
}IT[SZ + SZ];
Tree Merge(Tree a, Tree b) {
long long L = max(max(a.M + b.L, a.L + b.LR),a.L);
long long R = max(max(b.M + a.R, b.R + a.LR),b.R);
long long LR = max(max(a.LR,b.LR),max(a.R + b.L, a.LR + b.LR));
long long M = max(a.M + b.M, a.L + b.R);
Tree ret = { M,L,R,LR };
return ret;
}
void Make(int a, long long l, long long r) {
//printf("%d %lld %lld\n", a, l, r);
a += SZ;
IT[a] = { 0, l, -r, l - r };
while (a != 1) {
a >>= 1;
IT[a] = Merge(IT[a * 2], IT[a * 2 + 1]);
}
};
long long Get(int b, int e) {
b += SZ, e += SZ;
vector<int>T1, T2;
while (b <= e) {
if (b & 1) {
T1.push_back(b);
}
if (!(e & 1)) {
T2.push_back(e);
}
b = (b + 1) >> 1, e = (e - 1) >> 1;
}
reverse(T2.begin(), T2.end());
for (auto &t : T2)T1.push_back(t);
if (T1.empty())return 0;
Tree ret = IT[T1[0]];
for (int i = 1; i < T1.size(); i++)ret = Merge(ret, IT[T1[i]]);
return ret.M;
}
long long Solve(int b, int e, int bT, int eT) {
Make(b * 2, bT - b, INF);
Make(e * 2, -INF, eT - e);
long long res = Get(b * 2, e * 2);
Make(b * 2, -INF, INF);
Make(e * 2, -INF, INF);
return res;
}
}Right, Left;
int n, Q, LL[N_], RR[N_];
int main() {
//freopen("input.txt", "r", stdin);
int i, ck, a, b, c, d;
scanf("%d%d", &n, &Q);
for (i = 1; i < n; i++) {
scanf("%d%d", &LL[i], &RR[i]);
Left.Make(i * 2 + 1, LL[i] - i, RR[i] - i - 1);
Right.Make((n - i) * 2 + 1, LL[i] - (n-i), RR[i] - (n-i) - 1);
}
for (i = 1; i <= n; i++) {
Left.Make(i * 2, -INF, INF);
Right.Make(i * 2, -INF, INF);
}
while (Q--) {
scanf("%d", &ck);
if (ck == 1) {
scanf("%d%d%d", &a, &b, &c);
Left.Make(a * 2 + 1, b - a, c - a - 1);
Right.Make((n - a) * 2 + 1, b - (n-a), c - (n-a) - 1);
}
else {
scanf("%d%d%d%d", &a, &b, &c, &d);
if (a == c) {
printf("%d\n", max(b - d, 0));
}
else if (a < c) {
printf("%lld\n", Left.Solve(a, c, b, d));
}
else {
printf("%lld\n", Right.Solve(n + 1 - a, n + 1 - c, b, d));
}
}
}
return 0;
}
