/* package whatever; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.io.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
{
// your code goes here
long k,q,s=0;
int n,a,b,i;
Scanner sc
= new Scanner
(System.
in); n = sc.nextInt();
q = sc.nextLong();
long[] arr = new long[n+2];
for(i=0;i<q;i++){
a = sc.nextInt();
b = sc.nextInt();
k = sc.nextLong();
arr[a] = arr[a] + k;
arr[b+1] = arr[b+1] - k;
}
for(i=1;i<=n;i++){
arr[i] = arr[i] + arr[i-1];
max
= Math.
max(arr
[i
],max
); }
}
}
LyogcGFja2FnZSB3aGF0ZXZlcjsgLy8gZG9uJ3QgcGxhY2UgcGFja2FnZSBuYW1lISAqLwoKaW1wb3J0IGphdmEudXRpbC4qOwppbXBvcnQgamF2YS5sYW5nLio7CmltcG9ydCBqYXZhLmlvLio7CgovKiBOYW1lIG9mIHRoZSBjbGFzcyBoYXMgdG8gYmUgIk1haW4iIG9ubHkgaWYgdGhlIGNsYXNzIGlzIHB1YmxpYy4gKi8KY2xhc3MgSWRlb25lCnsKCXB1YmxpYyBzdGF0aWMgdm9pZCBtYWluIChTdHJpbmdbXSBhcmdzKSB0aHJvd3MgamF2YS5sYW5nLkV4Y2VwdGlvbgoJewoJCS8vIHlvdXIgY29kZSBnb2VzIGhlcmUKCQlsb25nIGsscSxzPTA7CgkJaW50IG4sYSxiLGk7CgkJU2Nhbm5lciBzYyA9IG5ldyBTY2FubmVyKFN5c3RlbS5pbik7CgkJbiA9IHNjLm5leHRJbnQoKTsKCQlxID0gc2MubmV4dExvbmcoKTsKCQlsb25nW10gYXJyID0gbmV3IGxvbmdbbisyXTsKCQkKCQlmb3IoaT0wO2k8cTtpKyspewoJCQlhID0gc2MubmV4dEludCgpOwoJCQliID0gc2MubmV4dEludCgpOwoJCQlrID0gc2MubmV4dExvbmcoKTsKCQkJYXJyW2FdID0gYXJyW2FdICsgazsKCQkJYXJyW2IrMV0gPSBhcnJbYisxXSAtIGs7CgkJfQoJCWxvbmcgbWF4ID0gSW50ZWdlci5NSU5fVkFMVUU7CgkJZm9yKGk9MTtpPD1uO2krKyl7CgkJCWFycltpXSA9IGFycltpXSArIGFycltpLTFdOwoJCQltYXggPSBNYXRoLm1heChhcnJbaV0sbWF4KTsKCQl9CgkJU3lzdGVtLm91dC5wcmludChtYXgpOwoJfQp9