Language: Java

#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, n) for (int i = 1; i <= (int)(n); i++)
using ll = long long;
using P = pair<ll,ll>;
#define pb push_back
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; }

/*
 string -> int : stoi(S);
 int -> string : to_string(N);
 Sのn文字以降をm文字取り出す : S.substr(n,m)
cout << fixed << setprecision(2) << 3.14 << endl; //3.1

 int: -2,147,483,648 ～ 2,147,483,647 (2×10^9)
 ll: -9,223,372,036,854,775,808 ~ 9,223,372,036,854,775,807 (9×10^18)

*/

int main() {

  ll n, m, count=0, ans=0;
  string s;
 
  cin >> n>>m;
  
  cout << n*m << endl;
}

Compiler output:
Main.java:1: error: illegal character: '#'
#include <bits/stdc++.h>
^
Main.java:1: error: class, interface, enum, or record expected
#include <bits/stdc++.h>
         ^
Main.java:4: error: illegal character: '#'
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
^
Main.java:4: error: class, interface, enum, or record expected
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
        ^
Main.java:4: error: class, interface, enum, or record expected
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
                                  ^
Main.java:4: error: class, interface, enum, or record expected
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
                                                ^
Main.java:5: error: illegal character: '#'
#define rep2(i, n) for (int i = 1; i <= (int)(n); i++)
^
Main.java:5: error: class, interface, enum, or record expected
#define rep2(i, n) for (int i = 1; i <= (int)(n); i++)
                                   ^
Main.java:5: error: class, interface, enum, or record expected
#define rep2(i, n) for (int i = 1; i <= (int)(n); i++)
                                                  ^
Main.java:7: error: unnamed classes are a preview feature and are disabled by default.
using P = pair<ll,ll>;
^
  (use --enable-preview to enable unnamed classes)
Main.java:7: error: ';' expected
using P = pair<ll,ll>;
                    ^
Main.java:8: error: illegal character: '#'
#define pb push_back
^
Main.java:8: error: class, interface, enum, or record expected
#define pb push_back
        ^
Main.java:9: error: '{' expected
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
                ^
Main.java:9: error: illegal start of type
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
                                                ^
Main.java:9: error: > or ',' expected
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
                                                       ^
Main.java:9: error: illegal start of type
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
                                                                            ^
Main.java:10: error: class, interface, enum, or record expected
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
^
Main.java:10: error: '{' expected
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
                ^
Main.java:10: error: illegal start of type
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
                                                ^
Main.java:10: error: > or ',' expected
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
                                                       ^
Main.java:10: error: illegal start of type
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
                                                                            ^
Main.java:28: error: not a statement
  cin >> n>>m;
          ^
Main.java:30: error: not a statement
  cout << n*m << endl;
              ^
24 errors