#include #include #define rep(i,b) for(int i=0;i=0;i--) #define rep1(i,b) for(int i=1;i using mpq = priority_queue, greater>; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (b ll sumv(const vector&a){ll res(0);for(auto&&x:a)res+=x;return res;} bool yn(bool a) { if(a) {cout << "Yes" << endl; return 1;} else {cout << "No" << endl; return 0;}} #define dame { cout << "No" << endl; return 0;} #define dame1 { cout << -1 << endl; return 0;} #define test(x) cout << "test" << x << endl; #define deb(x,y) cout << x << " " << y << endl; #define deb3(x,y,z) cout << x << " " << y << " " << z << endl; #define deb4(x,y,z,x2) cout << x << " " << y << " " << z << " " << x2 << endl; #define out cout << ans << endl; #define outv fore(yans , ans) cout << yans << "\n"; #define show(x) cerr<<#x<<" = "<; using pil = pair; using pli = pair; using pii = pair; using tp = tuple; using vi = vector; using vl = vector; using vs = vector; using vb = vector; using vpii = vector; using vpli = vector; using vpll = vector; using vpil = vector; using vvi = vector>; using vvl = vector>; using vvs = vector>; using vvb = vector>; using vvpii = vector>; using vvpli = vector>; using vvpll = vector; using vvpil = vector; using mint = modint1000000007; using vm = vector; using vvm = vector>; vector dx={1,0,-1,0,1,1,-1,-1},dy={0,1,0,-1,1,-1,1,-1}; ll gcd(ll a, ll b) { return a?gcd(b%a,a):b;} ll lcm(ll a, ll b) { return a/gcd(a,b)*b;} const double eps = 1e-10; const ll LINF = 1001002003004005006ll; const int INF = 1001001001; const int mod = 1000000007; struct combination { vector fact, ifact; combination(int n):fact(n+1),ifact(n+1) { assert(n < mod); fact[0] = 1; for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i; ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i; } mint operator()(int n, int k) { if (k < 0 || k > n) return 0; return fact[n]*ifact[k]*ifact[n-k]; } } com(10000005); int main(){ int h,w; cin>>h>>w; mint ans = 0; // rep(i,h+1) rep(j,w+1){ // if (i == 0 && j == 0) continue; // // mint tmp = mint(1) / mint(2).pow(i * j); // mint tmp = mint(2).pow(h*w - i * w - j * h + i * j) * com(h , i) * com(w , j); // deb(i , j); // cout << tmp.val() << endl; // if ((i+j) % 2 == 1) ans += tmp; // else ans -= tmp; // } rep(j,w+1){ mint j2 = mint(2).pow(j); mint z = 1 - j2; mint sum = mint(z).pow(h); sum *= com(w , j); int sign = 1; if (j%2 == 0) sign = -1; // cout << sum.val() << endl; ans += sum * sign; // show(j); } ans *= (1 - 2*((h + w + 1) % 2)); // cout << ans.val() << endl; // ans = mint(2).pow((ll)h*w) - ans; cout << ans.val() << endl; return 0; }