import sys
input = sys.stdin.readline

L,R=map(int,input().split())
A,B,C=map(int,input().split())

mod=998244353

R-=L

if R<C:
    print(0)
    exit()

if (R+1)-A-B<=0:
    print(0)
    exit()
"""
ANS=0
for i in range(1,R-C+2):
    print(((R+2)-A-B-i),i)
    ANS+=((R+2)-A-B-i)*i

print(ANS)
"""
def calcsum(c,n):
    return c*n*(n+1)//2-n*(n+1)*(2*n+1)//6

print(calcsum((R+2)-A-B,R-max(C,A+B)+1)%mod)