s, n = map(int,input().split())
coll = []
for i in range(n):
    x, y = map(int,input().split())
    coll.append([x,y,0])
 
coll = sorted(coll,key=lambda x:x[1])
 
found = 1
kills = 0
 
while(found):
    found = 0
    for i in range(n-1,-1,-1):
        if coll[i][0]<s and coll[i][2] is 0:
            if coll[i][1] is 0:
                s -= coll[i][0]
            else:
                s += coll[i][1]
            coll[i][2] = 1
            kills+=1
            found = 1
            break
 
if kills is n:
    print ('YES')
else:
    print ('NO')

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