#include #include using namespace std; using namespace atcoder; typedef long long int ll; typedef long double ld; typedef vector vi; typedef vector vvi; typedef vector vvvi; typedef vector vvvvi; typedef vector vb; typedef vector vvb; typedef vector vvvb; typedef vector vvvvb; typedef pair pi; typedef pair ppi; typedef pair pppi; typedef pair ppppi; #define FOR(i,l,r) for(ll i=l;i=l;i--) #define RREP(i,n) RFOR(i,0,n) #define ALL(x) x.begin(),x.end() #define F first #define S second #define BS(A,x) binary_search(ALL(A),x) #define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin()) #define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin()) #define COU(A,x) (UB(A,x)-LB(A,x)) #define sz(c) ((ll)(c).size()) /* #include namespace mp=boost::multiprecision; using Bint=mp::cpp_int; */ templateusing min_priority_queue=priority_queue,greater>; templateostream&operator<<(ostream&os,pair&p){os<istream&operator>>(istream&is,pair&p){is>>p.F>>p.S;return is;} templateostream&operator<<(ostream&os,vector&v){REP(i,sz(v))os<istream&operator>>(istream&is,vector&v){for(T&in:v)is>>in;return is;} templatebool chmax(T&a,T b){if(abool chmin(T&a,T b){if(b(a,b); auto y=convolution(a,b); auto z=convolution(a,b); vectorret(sz(a)+sz(b)-1); REP(i,sz(ret)){ ll v1=(y[i]-x[i])*m1_inv_m2%m2;if(v1<0)v1+=m2; ll v2=(z[i]-(x[i]+m1*v1)%m3)*m12_inv_m3%m3;if(v2<0)v2+=m3; ret[i]=(x[i]+m1*v1+m12_mod*v2)%mod; } return ret; } const ld EPS=1e-8; //* using mint=modint998244353; const ll mod=998244353; //*/ /* using mint=modint1000000007; const ll mod=1000000007; //*/ //using mint=modint; //* typedef vector vm; typedef vector vvm; typedef vector vvvm; typedef vector vvvvm; ostream&operator<<(ostream&os,mint&a){os<>N; vi A(N);cin>>A; REP(i,N)if(A[i]==0){ cout<<0<1){ cout<<0<1){ cout<<0<3){ cout<<0<1||a==0||b==0)return 0LL; return (a-1)*(b-1); }; if(N==2){ cout<