n,p = map(int,input().split())
arr = list(map(int,input().split()))
arr.append(0)
for i in range(n,0,-1):
    arr[i] = arr[i] - arr[i-1]
for i in range(p):
    l,r,num = map(int,input().split())
    arr[l-1] += num
    arr[r] -= num
for i in range(1,n):
    arr[i] += arr[i-1]

print(min(arr[:n]))