#include #define M_PI 3.14159265358979323846 using namespace std; //conversion //------------------------------------------ inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; } template inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); } inline int readInt() { int x; scanf("%d", &x); return x; } //typedef //------------------------------------------ typedef vector VI; typedef vector VVI; typedef vector VS; typedef pair PII; typedef pair TIII; typedef long long LL; typedef unsigned long long ULL; typedef vector VLL; typedef vector VVLL; //container util //------------------------------------------ #define ALL(a) (a).begin(),(a).end() #define RALL(a) (a).rbegin(), (a).rend() #define PB push_back #define MP make_pair #define SZ(a) int((a).size()) #define SQ(a) ((a)*(a)) #define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i) #define EXIST(s,e) ((s).find(e)!=(s).end()) #define SORT(c) sort((c).begin(),(c).end()) //repetition //------------------------------------------ #define FOR(i,s,n) for(int i=s;i<(int)n;++i) #define REP(i,n) FOR(i,0,n) #define MOD 1000000007 #define rep(i, a, b) for(int i = a; i < (b); ++i) #define trav(a, x) for(auto& a : x) #define all(x) x.begin(), x.end() #define sz(x) (int)(x).size() typedef long long ll; typedef pair pii; typedef vector vi; #define chmin(x,y) x=min(x,y) #define chmax(x,y) x=max(x,y) struct Edge { int to, from; ll cost; Edge(int from, int to, ll cost): from(from), to(to), cost(cost) {} }; typedef vector> AdjList; AdjList graph; typedef vector vec; typedef vector mat; mat mul(mat &A, mat &B) { mat C(A.size(), vec((int)B[0].size())); for(int i=0; i 0) { if(n & 1) B = mul(B, A); A = mul(A, A); n >>= 1; } return B; } int main() { //cin.tie(0); //ios::sync_with_stdio(false); //cout << fixed << setprecision(10); ll B, C, D; cin >> B >> C >> D; B %= MOD; C %=MOD; mat A(2, vec(2)); A[0][0] = C; A[0][1] = 0; A[1][1] = A[1][0] = 1; A = mat_pow(A, D + 1); cout << (A[1][0]+MOD-1)%MOD * B % MOD << endl; return 0; }