/*input
18 0

*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;
#define ld double
#define pii pair<int,int>
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=18;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=1e9+7;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
#define MP make_pair
ll mult(ll a,ll b){
    ll res=0LL;
    while(b){
        if(b&1) res=(res+a)%MOD;
        a=(a+a)%MOD;
        b>>=1;
    }
    return res%MOD;
}
ll mypow(ll a,ll b){
    ll res=1LL;
    while(b){
        if(b&1) res=res*a%MOD;
        a=a*a%MOD;
        b>>=1;
    }
    return res;
}
int ed[maxn][maxn];
bool vis[maxn];
int dp[(1<<18)];
inline int rec(int msk){
    if(dp[msk]!=-1) return dp[msk];
    vector<int> v;
    int z=msk;
    while(z){
        v.pb(__lg(lowb(z)));
        z-=lowb(z);
    }
    bool cl=1;
    REP(i,sz(v)){
        REP(j,i){
            if(!ed[v[i]][v[j]]){
                cl=0;
                break;
            }
        }
        if(!cl) break;
    }
    if(cl){
        return dp[msk]=1;
    }
    dp[msk]=INF;
    for(int s=msk&(msk-1);s;s=(s-1)&msk){
        MNTO(dp[msk],rec(msk^s)+rec(s));
    }
    return dp[msk];
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int n,m;
    cin>>n>>m;
    REP(i,m){
        int a,b;
        cin>>a>>b;
        --a;
        --b;
        ed[a][b]=ed[b][a]=1;
    }
    REP(i,(1<<n)) dp[i]=-1;
    cout<<rec((1<<n)-1);
}
#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define ld long double
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(), x.end()
#define mp(x, y) make_pair(x, y)
#define sz(li) (int) (li).size()
#define endE(li) li[sz(li) - 1]
#define vi vector<int>
#define vl vector<ll>
#define vvi vector<vector<int>>
#define vvl vector<vector<ll>>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pll>

template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v);
template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "(" << p.f << ", " << p.s << ")"; }
template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v) { cout << "[ "; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << " ]"; }
template<typename A> ostream& operator<<(ostream &cout, vector<vector<A>> const &v) { cout << "["; for (int i = 0; i < v.size(); i++) { if (i) { cout << " "; } cout << v[i]; if (i < v.size() - 1) { cout << endl; } } return cout << "]"; }
template<typename A, typename B> istream& operator>>(istream& cin, pair<A, B> &p) { cin >> p.first; return cin >> p.second; }

void solve() {
  ll x, y, z; cin >> x >> y >> z;

  if (y % x == 0) {
    cout << z * (y / x) - 1 << endl;
  } else {
    int price = (((y * 1.0) / x) * z);

    if ((price * 1.0) / z >= ((y * 1.0) / x)) {
      price--;
    }

    cout << price << endl;

  }
}

int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
  int t = 1;
  
  // cin >> t;

  while (t--) {
    solve();
  }
}