#if !__INCLUDE_LEVEL__
#include __FILE__

using PAIR = pair<int,int>;

struct Solver {
  void solve() {
    STR(s,t); INT(n);
    rep(i,n) s += "_" + t;
    print(s);
  }
} solver;

signed main(void){
  NO_SYNC_STD;
  dump("");
#ifdef __OPTIMIZE
  dump("OPTIMIZE ON");
#endif
#ifdef __INTERACTIVE
  dump("INTERACTIVE MODE");
#endif
#ifdef __INCLUDE_ATCODER_LIB
  dump("INCLUDE ATCODER LIB");
#endif
  solver.solve();
  return 0;
}

#else
// #define __OPTIMIZE
// #define __INCLUDE_ATCODER_LIB
// #define __INTERACTIVE
#define _GLIBCXX_DEQUE_BUF_SIZE 64
#ifdef __OPTIMIZE
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#endif
#include <bits/stdc++.h>
#ifdef __INCLUDE_ATCODER_LIB
#include <atcoder/all>
using namespace atcoder;
#endif
using namespace std;
#define overload4(a, b, c, d, e, ...) e
#define rep1(a)          for(decltype(a) i = 0, i##_len = (a); i < i##_len; ++i)
#define rep2(i, a)       for(decltype(a) i = 0, i##_len = (a); i < i##_len; ++i)
#define rep3(i, a, b)    for(decltype(b) i = (a), i##_len = (b); i < i##_len; ++i)
#define rep4(i, a, b, c) for(decltype(b) i = (a), i##_len = (b); i < i##_len; i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(a)          for(decltype(a) i = (a); i--;)
#define rrep2(i, a)       for(decltype(a) i = (a); i--;)
#define rrep3(i, a, b)    for(decltype(a) i = (b), i##_len = (a); i-- > i##_len;)
#define rrep4(i, a, b, c) for(decltype(a) i = (a)+((b)-(a)-1)/(c)*(c), i##_len = (a); i >= i##_len; i -= c)
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((int)(x).size())
#define yes(s) cout << ((s)?"Yes":"No") << "\n";
#define bit(n) (1LL << ((int)(n)))
#define get1bit(x,n) (((x) >> (int)(n)) & 1)
#define INF ((1 << 30) - 1)
#define INFL (1LL << 60)
#define PRECISION std::setprecision(16)
#define INT(...) int __VA_ARGS__; input(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__; input(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; input(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; input(__VA_ARGS__)
#define VEC(type, name, size) vector<type> name(size); input(name)
#ifdef __INTERACTIVE
#define NO_SYNC_STD
#define ENDL std::endl
#else
#define NO_SYNC_STD std::cin.tie(nullptr);ios::sync_with_stdio(false)
#define ENDL "\n"
#endif
#ifdef __LOCAL
#include <dump.hpp>
#define dump(...) DUMPOUT << "  " << string(#__VA_ARGS__) << ": " << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl << "    ", dump_func(__VA_ARGS__)
#else
#define dump(...)
#endif
using ll=long long;using ull=unsigned long long;using ld=long double;template<class T> using V=vector<T>;template<class T> using VV=vector<vector<T>>;template<class T> using PQ=priority_queue<T,V<T>,greater<T>>;
template<class T> istream &operator>>(istream &is,complex<T> &v){T x,y; is >> x >> y;v.real(x);v.imag(y);return is;}
template<class T> istream &operator>>(istream &is,V<T> &v){for(auto&& e:v)is >> e;return is;}
template<class T,class U> istream &operator>>(istream &is,pair<T,U> &v){is >> v.first >> v.second;return is;}
template<class T,size_t n> istream &operator>>(istream &is,array<T,n> &v){for(auto&& e:v)is >> e;return is;}
template<class... A> void input(A&&... args){(cin >> ... >> args);}
template<class... A> void print_rest(){cout << ENDL;}
template<class T,class... A> void print_rest(const T& first,const A&... rest){cout << " " << first;print_rest(rest...);}
template<class T,class... A> void print(const T& first,const A&... rest){cout << fixed << PRECISION << first;print_rest(rest...);}
template<class T,class... A> void die(const T& first,const A&... rest){cout << fixed << PRECISION << first;print_rest(rest...);exit(0);}
template<class T> inline string join(const T& v,string sep=" "){if(v.size() == 0)return "";stringstream ss;for(auto&& e:v)ss << sep << e;return ss.str().substr(sz(sep));}
V<string> split(const string &s,char sep=' ') {V<string> ret;stringstream ss(s);string buf;while(getline(ss,buf,sep))ret.push_back(buf);return ret;}
template<class T> inline string padding(const T& v,int length,char pad=' ',bool left=false){stringstream ss;ss << (left?std::left:std::right) << setw(length) << setfill(pad) << v;return ss.str();}
template<class T> V<T> make_vec(size_t n,T a){return V<T>(n,a);}
template<class... Ts> auto make_vec(size_t n,Ts... ts){return V<decltype(make_vec(ts...))>(n,make_vec(ts...));}
template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;} return 0;}
template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;} return 0;}
template<class T,class F> pair<T,T> binarysearch(T ng,T ok,T eps,F f,bool sign=false){while(abs(ng-ok)>eps){auto mid=ng+(ok-ng)/2;if(sign^f(mid)){ok=mid;}else{ng=mid;}}return{ng,ok};}
template<class T> constexpr T cdiv(T x,T y){return (x+y-1)/y;}
template<class T> constexpr bool between(T a,T x,T b){return(a<=x&&x<b);}
template<class T> inline int lower_index(V<T>&a,T x){return (int)distance(a.begin(),lower_bound(all(a),x));}
template<class T> inline int upper_index(V<T>&a,T x){return (int)distance(a.begin(),upper_bound(all(a),x));}
template<class T> inline V<T> transposed(V<T>& A){int h=sz(A),w=sz(A[0]);V<T> tA(w);rep(i,h)rep(j,w)tA[j].push_back(A[i][j]);return tA;}
template<class T> constexpr T pos1d(T y,T x,T h,T w){assert(between(T(0),y,h));assert(between(T(0),x,w));return y*w+x;}
template<class T> constexpr pair<T,T> pos2d(T p,T h,T w){T y=p/w,x=p-y*w;assert(between(T(0),y,h));assert(between(T(0),x,w));return{y,x};}
template<class T> constexpr T sign(T n) {return (n > 0) - (n < 0);}
inline string upper(string s) {for(auto&& e: s) e = between('a',e,(char)('z'+1)) ? e - ('a'-'A') : e;return s;}
inline string lower(string s) {for(auto&& e: s) e = between('A',e,(char)('Z'+1)) ? e + ('a'-'A') : e;return s;}
inline string replace(string s, map<char, int> &from, V<int> &to) {for (auto&& e: s) e = '0' + (char)(to[from[e]]);return s;}
constexpr ll modpow(ll x,ll n,ll m=1152921504606846976LL){ll ret=1;for(;n>0;x=x*x%m,n>>=1)if(n&1)ret=ret*x%m;return ret;}
constexpr ll safe_mod(ll x, ll m) {x%=m;if(x<0)x+=m;return x;}
constexpr ll keta(ll n, ll base = 10LL) {ll ret = 0; while(n > 0) {n /= base, ret++;} return ret;}
constexpr int pcnt(ll x) {return __builtin_popcountll(x);}
constexpr int flog(ll x) {return 63 - __builtin_clzll(x);}
constexpr int clog(ll x) {return (x==1LL)?0:(64-__builtin_clzll(x-1LL));}
constexpr ll nC2(ll n) {return n*(n-1)/2;}
constexpr ld deg2rad(ll degree){return (ld)degree * M_PI/180;}
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx6[6] = {1, 0, -1, 0, 1, -1};
const int dy6[6] = {0, 1, 0, -1, 1, -1};
const int dx8[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy8[8] = {0, 1, 0, -1, 1, 1, -1, -1};
#endif