69B - Bets - CodeForces Solution

import math
from collections import deque


n,m = map(int,input().split())
athletes = []
for i in range(m):
    l,r,m,c = map(int,input().split())
    athletes.append((l,r,m,c))
    
total = 0
for i in range(n):
    sec = i + 1
    fastest = None
    for j in range(len(athletes)):
        if athletes[j][0] <= sec and athletes[j][1] >= sec:
            if fastest == None:
                fastest = j
                continue
            if athletes[j][2] < athletes[fastest][2]:
                fastest = j
    if fastest == None:
        continue
    total += athletes[fastest][3]
print(total)