[백준] 1292번 : 쉽게 푸는 문제 - Python(파이썬)

https://www.acmicpc.net/problem/1292

n,m=map(int,input().split())
num=0
a=0
count=0
i=1
while 1:
    count+=i
    a+=i*i
    if n-count-1<=i and n!=1:
        num-=a
        num-=(n-count-1)*(i+1)
        n=10000
    if m-count-1<=i:
        num+=a
        num+=(m-count)*(i+1)
        break
    i+=1
print(num)