l,m = input().split() l,m = int(l),int(m) s = [0] t = [0] s += [0]*m t += [0]*m l_ = [0] num = 0 for b in range(1,m+1): s[b],t[b] = input().split() s[b],t[b] = int(s[b]),int(t[b]) for a in range(0,l-1): l_ += [0] for b in range(1,3): for a in range(s[b],t[b]+1): l_[a] = 1 for a in range(0,l): if l_[a] == 0: num += 1 print(num)

这篇代码输出结果总是少一个 都来帮我看看【大哭】