#include using namespace std; #define LOCAL #pragma region Macros typedef long long ll; #define ALL(x) (x).begin(),(x).end() const long long MOD=1000000007; // const long long MOD=998244353; const int INF=1e9; const long long IINF=1e18; const int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1}; const char dir[4]={'D','R','U','L'}; template istream &operator>>(istream &is,vector &v){ for (T &x:v) is >> x; return is; } template ostream &operator<<(ostream &os,const vector &v){ for (int i=0;i ostream &operator<<(ostream &os,const pair &p){ os << '(' << p.first << ',' << p.second << ')'; return os; } template ostream &operator<<(ostream &os,const map &m){ os << '{'; for (auto itr=m.begin();itr!=m.end();++itr){ os << '(' << itr->first << ',' << itr->second << ')'; if (++itr!=m.end()) os << ','; --itr; } os << '}'; return os; } template ostream &operator<<(ostream &os,const set &s){ os << '{'; for (auto itr=s.begin();itr!=s.end();++itr){ os << *itr; if (++itr!=s.end()) os << ','; --itr; } os << '}'; return os; } void debug_out(){cerr << '\n';} template void debug_out(Head&& head,Tail&&... tail){ cerr << head; if (sizeof...(Tail)>0) cerr << ", "; debug_out(move(tail)...); } #ifdef LOCAL #define debug(...) cerr << " ";\ cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n';\ cerr << " ";\ debug_out(__VA_ARGS__) #else #define debug(...) 42 #endif template T gcd(T x,T y){return y!=0?gcd(y,x%y):x;} template T lcm(T x,T y){return x/gcd(x,y)*y;} template inline bool chmin(T1 &a,T2 b){ if (a>b){a=b; return true;} return false; } template inline bool chmax(T1 &a,T2 b){ if (a class modint{ using i64=int64_t; using u32=uint32_t; using u64=uint64_t; public: u32 v; constexpr modint(const i64 x=0) noexcept :v(x<0?mod-1-(-(x+1)%mod):x%mod){} constexpr u32 &value() noexcept {return v;} constexpr const u32 &value() const noexcept {return v;} constexpr modint operator+(const modint &rhs) const noexcept {return modint(*this)+=rhs;} constexpr modint operator-(const modint &rhs) const noexcept {return modint(*this)-=rhs;} constexpr modint operator*(const modint &rhs) const noexcept {return modint(*this)*=rhs;} constexpr modint operator/(const modint &rhs) const noexcept {return modint(*this)/=rhs;} constexpr modint &operator+=(const modint &rhs) noexcept { v+=rhs.v; if (v>=mod) v-=mod; return *this; } constexpr modint &operator-=(const modint &rhs) noexcept { if (v0){ if (exp&1) res*=self; self*=self; exp>>=1; } return res; } constexpr modint &operator++() noexcept {if (++v==mod) v=0; return *this;} constexpr modint &operator--() noexcept {if (v==0) v=mod; return --v,*this;} constexpr modint operator++(int) noexcept {modint t=*this; return ++*this,t;} constexpr modint operator--(int) noexcept {modint t=*this; return --*this,t;} template friend constexpr modint operator+(T x,modint y) noexcept {return modint(x)+y;} template friend constexpr modint operator-(T x,modint y) noexcept {return modint(x)-y;} template friend constexpr modint operator*(T x,modint y) noexcept {return modint(x)*y;} template friend constexpr modint operator/(T x,modint y) noexcept {return modint(x)/y;} constexpr bool operator==(const modint &rhs) const noexcept {return v==rhs.v;} constexpr bool operator!=(const modint &rhs) const noexcept {return v!=rhs.v;} constexpr bool operator!() const noexcept {return !v;} friend istream &operator>>(istream &s,modint &rhs) noexcept { i64 v; rhs=modint{(s>>v,v)}; return s; } friend ostream &operator<<(ostream &s,const modint &rhs) noexcept { return s< struct Combination{ vector _fac,_inv,_finv; Combination(int n):_fac(n+1),_inv(n+1),_finv(n+1){ _fac[0]=_finv[n]=_inv[0]=1; for (int i=1;i<=n;++i) _fac[i]=_fac[i-1]*i; _finv[n]/=_fac[n]; for (int i=n-1;i>=0;--i) _finv[i]=_finv[i+1]*(i+1); for (int i=1;i<=n;++i) _inv[i]=_finv[i]*_fac[i-1]; } M fac(int k) const {return _fac[k];} M finv(int k) const {return _finv[k];} M inv(int k) const {return _inv[k];} M P(int n,int r) const { if (n<0||r<0||n; int main(){ cin.tie(0); ios::sync_with_stdio(false); Combination COM(2000010); int X,Y,Z; cin >> X >> Y >> Z; int N=X+Y+Z; if (!N){cout << 0 << '\n'; return 0;} vector A(N+1,0); mint power=mint(2).pow(N+1); for (int i=0;i<=N;++i) A[i]+=COM.C(N+1,i)*power; A[0]-=1; mint sum0=0,sum1=0; for (int i=0;i<=N;++i,sum0*=2,sum1*=2){ mint org=A[i]; A[i]+=sum0-sum1; sum0+=org; swap(sum0,sum1); } mint ans=0; for (int i=0;i<=N;++i){ mint add=COM.C(i,X)*COM.C(i,Y)*COM.C(i,Z)*A[i]; if ((i+X+Y+Z)&1) ans-=add; else ans+=add; } cout << ans/2 << '\n'; }