from re import split import sys n,m= map(int,sys.stdin.readline().split()) costs = [n] #print(costs) for line in sys.stdin: a,b = map(int,line.split()) if a <= n: costs.append(n-b) #print(costs) costs.sort() print(costs[0])
from re import split import sys n,m= map(int,sys.stdin.readline().split()) costs = [n] #print(costs) for line in sys.stdin: a,b = map(int,line.split()) if a <= n: costs.append(n-b) #print(costs) costs.sort() print(costs[0])