#include using namespace std; #define fs first #define sc second #define pb push_back #define mp make_pair #define eb emplace_back #define ALL(A) A.begin(),A.end() #define RALL(A) A.rbegin(),A.rend() typedef long long LL; typedef pair P; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } template T gcd(T a,T b){return b?gcd(b,a%b):a;} const LL mod=1000000007; const LL LINF=1LL<<62; const int INF=1<<30; int dx[]={1,0,-1,0,1,-1,1,-1}; int dy[]={0,1,0,-1,1,-1,-1,1}; int M_N = 400000; vector fact; vector inver(M_N+1); LL combi(int n,int r){ if(n 0){ if(n&1){ x=x*a%mod; } a=a*a%mod; n >>= 1; } return x; } void set_combi(){ LL s=1; fact.push_back(1); for(int i=1;i<=M_N;i++){ s*=i; s%=mod; fact.push_back(s); } inver[M_N]=fpow(fact[M_N],mod-2); for(int i=M_N-1;i>=0;i--){ inver[i]=inver[i+1]*(i+1)%mod; } } int main(){ set_combi(); LL n, k;cin >> n >> k; k %= mod; LL S = k * (k + 1) %mod; S = S * fpow(2, mod - 2) %mod; LL ans = 0; for (LL i = 0; i < n; i++) { ans = (ans + fpow(S, i) * combi(n, i) %mod * fpow(k, n - i) %mod)%mod; } cout << ans << endl; return 0; }