Submission #65679453

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def li():return list(map(int,input().split()))
a,b,c,d=li()
mod=998244353
#リンゴ＜バナナ、リンゴ＜ブドウ、オレンジ＜ブドウ
class Comb:
    def __init__(self, sup, mod=998244353):
        self.sup = sup
        self.mod = mod
        self.inv = [1]
        self.fact = [1]
        for i in range(1, self.sup + 1):
            self.fact.append((self.fact[-1] * i) % self.mod)
            self.inv.append((self.inv[-1] * pow(i, -1, mod)) % self.mod)
    def C(self, n, r):
        assert self.sup > n
        if r > n:
            return 0
        return (self.fact[n] * self.inv[r] * self.inv[n - r]) % self.mod
 
 
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def li():return list(map(int,input().split()))

a,b,c,d=li()
mod=998244353
#リンゴ＜バナナ、リンゴ＜ブドウ、オレンジ＜ブドウ
class Comb:
    def __init__(self, sup, mod=998244353):
        self.sup = sup
        self.mod = mod
        self.inv = [1]
        self.fact = [1]
        for i in range(1, self.sup + 1):
            self.fact.append((self.fact[-1] * i) % self.mod)
            self.inv.append((self.inv[-1] * pow(i, -1, mod)) % self.mod)

    def C(self, n, r):
        assert self.sup > n
        if r > n:
            return 0
        return (self.fact[n] * self.inv[r] * self.inv[n - r]) % self.mod

cmb=Comb(a+b+c+d+3)
ans=0
for i in range(c+1):
    ans+=(cmb.C(c+d-i-1,c-i)*cmb.C(a+i+b,b))%mod
    ans%=mod
print(ans)

Submission Info

Judge Result