题解 | 小红的优惠券
小红的优惠券
https://www.nowcoder.com/practice/e991a011f96444f3a6ad57943d39f4ad
n,m = map(int, input().split())
c = {}
k = []
l = 0
for i in range(m):
a,b = map(int, input().split())
c[a] = b
for j in c.keys():
if n >= j:
k.append(c[j])
if len(k) != 0:
l = max(k)
print(n - l)
