#include "bits/stdc++.h" using namespace std; using ll=long long; using vll=vector< ll>; using vvll=vector< vll>; using vvvll=vector< vvll>; using vvvvll=vector; using dd=double; using vdd=vector< dd>; using vvdd=vector< vdd>; using pll=pair; using tll=tuple; using qll=tuple; constexpr ll INF = 1LL << 60; struct Fast{ Fast(){ cin.tie(0); ios::sync_with_stdio(false); cout<::max_digits10); } } fast; #define REPS(i, S, E) for (ll i = (S); i <= (E); i++) #define REP(i, N) REPS(i, 0, (N)-1) #define DEPS(i, S, E) for (ll i = (E); i >= (S); i--) #define DEP(i, N) DEPS(i, 0, (N)-1) #define rep(i, S, E) for (ll i = (S); i <= (E); i++) #define dep(i, E, S) for (ll i = (E); i >= (S); i--) #define each(e, v) for (auto&& e : v) #define ALL(v) (v).begin(), (v).end() #define RALL(v) (v).rbegin(), (v).rend() template inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; }return false; } template inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; }return false; } template inline T MaxE(vector&v,ll S,ll E){ T m=v[S]; rep(i,S,E)chmax(m,v[i]); return m; } template inline T MinE(vector&v,ll S,ll E){ T m=v[S]; rep(i,S,E)chmin(m,v[i]); return m; } template inline T MaxE(vector &v) { return MaxE(v,0,(ll)v.size()-1); } template inline T MinE(vector &v) { return MinE(v,0,(ll)v.size()-1); } template inline T Sum(vector &v,ll S,ll E){ T s=T(); rep(i,S,E)s+=v[i]; return s; } template inline T Sum(vector &v) { return Sum(v,0,v.size()-1); } template inline ll sz(T &v){ return (ll)v.size(); } inline ll CEIL(ll a,ll b){ return (a<0) ? -(-a/b) : (a+b-1)/b; } inline ll FLOOR(ll a,ll b){ return -CEIL(-a,b); } //vector用テンプレート template inline vector& operator+=(vector &a,const vector &b){ for (ll i=0; i<(ll)a.size(); i++) a[i]+=b[i]; return a; } template inline vector& operator-=(vector &a,const vector &b){ for (ll i=0; i<(ll)a.size(); i++) a[i]-=b[i]; return a; } template inline vector& operator*=(vector &a,const vector &b){ for (ll i=0; i<(ll)a.size(); i++) a[i]*=b[i]; return a; } template inline vector& operator/=(vector &a,const vector &b){ for (ll i=0; i<(ll)a.size(); i++) a[i]/=b[i]; return a; } template inline vector& operator%=(vector &a,const vector &b){ for (ll i=0; i<(ll)a.size(); i++) a[i]%=b[i]; return a; } template inline vector& operator+=(vector &a,S b){ for (T &e: a) e+=b; return a; } template inline vector& operator-=(vector &a,S b){ for (T &e: a) e-=b; return a; } template inline vector& operator*=(vector &a,S b){ for (T &e: a) e*=b; return a; } template inline vector& operator/=(vector &a,S b){ for (T &e: a) e/=b; return a; } template inline vector& operator%=(vector &a,S b){ for (T &e: a) e%=b; return a; } template inline vector operator+(const vector &a,S b){ vector c=a; return c+=b; } template inline vector operator-(const vector &a,S b){ vector c=a; return c-=b; } template inline vector operator*(const vector &a,S b){ vector c=a; return c*=b; } template inline vector operator/(const vector &a,S b){ vector c=a; return c/=b; } template inline vector operator%(const vector &a,S b){ vector c=a; return c%=b; } template inline vector operator-(S b,const vector &a){ vector c=-a; return c+=b; } template inline vector operator-(const vector &a){ vector c=a; return c*=(-1); } template inline ostream &operator<<(ostream &os,const vector &a){ for (ll i=0; i<(ll)a.size(); i++) os<<(i>0?" ":"")< struct mll_{ ll val; mll_(ll v = 0): val(v % MOD){ if (val < 0) val += MOD; } mll_ operator - () const { return -val; } mll_ operator + (const mll_ &b) const { return val + b.val; } mll_ operator - (const mll_ &b) const { return val - b.val; } mll_ operator * (const mll_ &b) const { return val * b.val; } mll_ operator / (const mll_ &b) const { return mll_(*this) /= b; } mll_ operator + (ll b) const { return *this + mll_(b); } mll_ operator - (ll b) const { return *this - mll_(b); } mll_ operator * (ll b) const { return *this * mll_(b); } friend mll_ operator + (ll a,const mll_ &b) { return b + a; } friend mll_ operator - (ll a,const mll_ &b) { return -b + a; } friend mll_ operator * (ll a,const mll_ &b) { return b * a; } friend mll_ operator / (ll a,const mll_ &b) { return mll_(a)/b; } mll_ &operator += (const mll_ &b) { val=(val+b.val)%MOD; return *this; } mll_ &operator -= (const mll_ &b) { val=(val+MOD-b.val)%MOD; return *this; } mll_ &operator *= (const mll_ &b) { val=(val*b.val)%MOD; return *this; } mll_ &operator /= (const mll_ &b) { ll c=b.val,d=MOD,u=1,v=0; while (d){ ll t = c / d; c -= t * d; swap(c,d); u -= t * v; swap(u,v); } val = val * u % MOD; if (val < 0) val += MOD; return *this; } mll_ &operator += (ll b) { return *this += mll_(b); } mll_ &operator -= (ll b) { return *this -= mll_(b); } mll_ &operator *= (ll b) { return *this *= mll_(b); } mll_ &operator /= (ll b) { return *this /= mll_(b); } bool operator == (const mll_ &b) const { return val == b.val; } bool operator != (const mll_ &b) const { return val != b.val; } bool operator == (ll b) const { return *this == mll_(b); } bool operator != (ll b) const { return *this != mll_(b); } friend bool operator == (ll a,const mll_ &b) { return mll_(a) == b.val; } friend bool operator != (ll a,const mll_ &b) { return mll_(a) != b.val; } friend ostream &operator << (ostream &os,const mll_ &a) { return os << a.val; } friend istream &operator >> (istream &is,mll_ &a) { return is >> a.val; } static mll_ Combination(ll a,ll b){ chmin(b,a-b); if (b<0) return mll_(0); mll_ c = 1; rep(i,0,b-1) c *= a-i; rep(i,0,b-1) c /= i+1; return c; } }; using mll = mll_<1000000007LL>; //using mll = mll_<998244353LL>; using vmll = std::vector; using vvmll = std::vector; using vvvmll = std::vector; using vvvvmll = std::vector; #if 0 #include using namespace atcoder; #endif struct Combination{ vmll f,g; Combination(){} Combination(ll maxN): f(maxN+1,1),g(maxN+1){ InitSub(maxN); } void init(ll maxN){ f.resize(maxN+1,1); g.resize(maxN+1); InitSub(maxN); } mll operator () (ll n,ll r){ return (n<0||r<0||n inline T POW(T a,ll n){ T r=1; for (; n>0; n>>=1,a*=a){ if (n&1)r*=a; } return r; } inline ll POW(int a,ll n){ return POW((ll)a,n); } void solve() { ll n,k,m; cin >> n >> k >> m; if (n==1){ cout << 1 << '\n'; return; } Combination cmb(n+10); mll ans=0; if (m==1){ rep(fa,1,n){ if (k%fa==0){ ans+=cmb.P(n-1,fa-1)*POW(mll(n),n-fa); } } } else{ vmll f(n); f[1]=1; rep(R,2,n-1){ if (R<=k){ f[R] = f[R-1]*(R-1)+POW(mll(n),R-1); } else{ f[R] = f[R-1]*(R-1) + POW(mll(n),R-1) - cmb.P(R-1,k)*POW(mll(n),R-k-1); } } rep(R,1,n-1){ ll fa=n-R; ans+=f[R]*cmb.P(n-2,fa-1); } rep(fa,2,n){ ll R=n-fa; if (k%fa>=1){ ans+= cmb.P(n-2,fa-2)*POW(mll(n),R); } } } cout << ans << '\n'; //mll ans=0; //if (m==1){ // rep(f,1,n){ // if (k%f==0){ // ans+=cmb.P(n-1,f-1)*POW(mll(n),n-f); // } // } //} //else{ // rep(f,2,n){ // if (k%f!=0){ // ans+=cmb.P(n-2,f-2)*POW(mll(n),n-f); // } // } //} //cout << ans << '\n'; } int main(){ #if 1 solve(); #else ll t; cin >> t; rep(i, 0, t-1){ solve(); } #endif return 0; }