def main1(n,m,b,lr):
  b=[x*(-1)**i for i,x in enumerate(b)]
  rary=[set() for _ in range(n)]
  for l,r in lr:rary[l-1].add(r)
  ary=[0]*(n+1)
  now=0
  for i in range(n):
    now-=ary[i]
    stc=set()
    d=0
    while rary[i]:
      r=rary[i].pop()
      stc.add(r)
      d=b[i]-now
    if stc:
      stc=list(stc)
      stc.sort()
      for x,y in zip(stc[0:],stc[1:]):
        rary[x].add(y)
      ary[stc[0]]+=d
      now+=d
    if b[i]==now:
      pass
    else:
      return False
  return True
import sys
input=sys.stdin.readline
if __name__=='__main__':
  n,m=map(int,input().split())
  b=list(map(int,input().split()))
  lr=[list(map(int,input().split())) for _ in range(m)]
  ret1=main1(n,m,b,lr)
  print('YES' if ret1 else 'NO')