Go: package main

import "fmt"

func main() {
	var F int
	fmt.Scan(&F)
	fmt.Println((F - 30)/2)
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
using namespace std;
int main(void) {
  int N;
  cin >> N;
  cout << (N-30)/2 << endl;
  return 0;
}

C++: #include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <regex>
#define ull unsigned long long
#define REP(i,n) for(int i = 0; i < n; i++)
#define FOR(i,j,n) for(int i = j; i < n; i++)
#define RFOR(i,j,n) for(int i = j-1; i >= n; i--)
#define PREC(n) fixed << setprecision(n)
#define print_array(v) REP(__k, v.size()) { cout << v[__k]; if(__k != v.size()-1) cout << " "; else cout << endl; }
using namespace std;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int F;
	cin >> F;
	cout << (F - 30) / 2 << endl;
}

C++: #include <stdio.h>
int main(void) {
	int F;
	scanf("%d", &F);
	F = (F - 30) / 2;
	printf("%d\n", F);
	return 0;
}

C++: #include <iostream>
using namespace std;
int main(void){
       int a;
       cin>>a;
       cout<<(a-30)/2<<endl;
       return 0;
    
}

C++: #include<bits/stdc++.h>

using namespace std;

main(){
	int F;
	int C;
	cin >> F;
	C=(F-30)/2;
	printf("%d\n",C);
}

C++: #include <iostream>
using namespace std;
int main(){

int C , F ;
cin >> F ;

C = ( F - 30 ) / 2;

cout << C << endl ;

return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int main(){
   int s;
   cin >> s;
   cout << (s-30)/2 << endl;
   return 0;
}

C++: #include <iostream>
using namespace std;

int main()
{
	int f;
	cin >>f;
	cout << (f - 30) / 2 << endl;
	
	
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;

int main() {
    int F;
    cin >> F;
    cout << (F-30)/2 << endl;
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define LINF (ll)INF*INF
#define MOD 1000000007
#define rep(i,n) for(int i=0;i<(n);i++)
#define loop(i,a,n) for(int i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

#define int ll //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;
typedef vector<pii> vp;

int gcd(int a, int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int lcm(int a, int b){
    return a/gcd(a,b)*b;
}


signed main(void) {
    int n;
    cin >> n;
    cout << (n-30)/2 << endl;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
using namespace std;
#define Would
#define you


int main() {
	int n;
	cin >> n;
	cout << (n - 30) / 2 << endl;
}

C++: #include <iostream>
using namespace std;

int main() {
    int f; cin >> f;
    cout << (f - 30) / 2 << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
typedef long long ll;
typedef pair<int, int> P;

int main() {
    int f;
    cin >> f;
    cout << (f-30)/2 << endl;

    return 0;
}

C++: #include <bits/stdc++.h>

#define rep(i, n) for (int(i) = 0; (i) < (int)(n); (i)++)
#define repr(i, n) for (int(i) = (n); (i) >= 0; (i)--)
#define repf(i, m, n) for (int(i) = (m); (i) < (n); (i)++)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define inf 1e9

template <class T>
bool chmax(T &a, const T &b)
{
    if (a < b)
    {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
bool chmin(T &a, const T &b)
{
    if (b < a)
    {
        a = b;
        return 1;
    }
    return 0;
}

using namespace std;
using ll = long long;

int kakuinowa(int num, int a, int n)
{
    string tmp = to_string(num);
    vector<int> keta(10, 0);

    for (int i = 0; i < tmp.size(); i++)
    {
        keta[i] = tmp[i] - '0';
    }

    ll sum = accumulate(all(keta), 0);

    return pow(sum + a, n);
}

int main(int argc, char const *argv[])
{
    int f;
    cin >> f;
    cout << (f - 30) / 2 << endl;

    return 0;
}

C++: #include <iostream>
using namespace std;
int main(void){
    int F,C;
    cin >>F;
    C=(F-30)/2;
    cout <<C<<endl;
}

C++: #include<iostream>
using namespace std;
int main() {
	int a;
	cin >> a;
	cout << (a - 30) / 2 << endl;
}

C++: #include<stdio.h>
int main(void) {
	int F;
	scanf("%d", &F);
	F = (F - 30) / 2;
	printf("%d\n", F);
	return 0;
}

C++: // Celcius and Fahrenheit 2018/12/28

#include <iostream>
using namespace std;

int main() {
    int F, C;
    cin >> F;
    cout << (F - 30) / 2 << '\n';
    return 0;
}

C++: #include <iostream>
using namespace std;

int main(){
    int a,b;
    cin >> a ;
    b = (a-30)/2;
    cout << b << endl;
    return 0;
}

C++: #include <iostream>
using namespace std;
int main(void){
    int f;
    cin >> f;
    cout << (f-30)/2 << endl;
}

C++: #include<iostream>
using namespace std;

int main(){
  int F=0;
  cin >> F;
  cout << (F-30)/2 << endl;
  return 0;
}

C++: #include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>

#include <iostream>
#include <complex>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>

#include <functional>
#include <cassert>

typedef long long ll;
using namespace std;

#define debug(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;

#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 100010


int main(){
  int f;

  cin >> f;

  cout << (f-30) / 2 << endl;
  
  return 0;
}

C++: #include <stdio.h>
#include <iostream>

using namespace std;

int main(void)
{
	int input, output;

	cin >> input;

	output = (input - 30) / 2;

	cout << output << endl;
}

C++: #include <iostream>
using namespace std;
int main(void){
    // Your code here!
    int a;
    cin>>a;
    a-=30;
    cout<<a/2<<endl;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int F; cin >> F;
    int C = (F -30) / 2;
    
    cout << C << endl;

    return 0;
}

C++: #include<stdio.h>
int main(void)
{
	int a,b,C,F;
	scanf("%d",&F,&a,&b);
	a=30;
	b=2;
	C=(F-a)/b;
	printf("%d\n",C);
	return 0;
}

C++: #include<iostream>
using namespace std;

int main()
{
    int f;

    cin >> f;

    cout << ( f - 30 ) / 2 << endl;

    return 0;
}