1
s, n = map(int, input().split())
2
d = []
3
for i in range(n):
4
    x, y = map(int, input().split())
5
    d.append((x, y))
6
    
7
d = sorted(d)
8
 
9
result = 'YES'
10
 
11
for (x, y) in d:
12
    if s > x:
13
        s += y
14
    else:
15
        result = 'NO'
16
        break
17
 
18
print(result)
19