Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
using str = string;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
const double PI = 3.141592653589793238;
const ll mod = 1000000007;
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define REP(i, m, n) for (int i = m; i < (int)n; i++)
#define all(a) (a).begin(), (a).end()
#define allg(a) (a).begin(), (a).end(), greator<>()
#define d20 std::setprecision(20)
#define veci vector<int>
#define vecll vector<long long int>
#define vecd vector<double>
template <typename T>
T lcm(T a, T b)
{
	return a / __gcd(a, b) * b;
}
void comb(vector<vector<long long int>> &v)
{
	for (int i = 0; i < v.size(); i++)
	{
		v[i][0] = 1;
		v[i][i] = 1;
	}
	for (int k = 1; k < v.size(); k++)
	{
		for (int j = 1; j < k; j++)
		{
			v[k][j] = (v[k - 1][j - 1] + v[k - 1][j]);
		}
	}
}

int main()
{
	ll n, a, b;
	cin >> n >> a >> b;
	cout << min(n % (a + b), a) + n / (a + b) * a << endl;
	return 0;
}#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
using str = string;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
const double PI = 3.141592653589793238;
const ll mod = 1000000007;
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define REP(i, m, n) for (int i = m; i < (int)n; i++)
#define all(a) (a).begin(), (a).end()
#define allg(a) (a).begin(), (a).end(), greator<>()
#define d20 std::setprecision(20)
#define veci vector<int>
#define vecll vector<long long int>
#define vecd vector<double>
template <typename T>
T lcm(T a, T b)
{
	return a / __gcd(a, b) * b;
}
void comb(vector<vector<long long int>> &v)
{
	for (int i = 0; i < v.size(); i++)
	{
		v[i][0] = 1;
		v[i][i] = 1;
	}
	for (int k = 1; k < v.size(); k++)
	{
		for (int j = 1; j < k; j++)
		{
			v[k][j] = (v[k - 1][j - 1] + v[k - 1][j]);
		}
	}
}

int main()
{
	ll n, a, b;
	cin >> n >> a >> b;
	cout << min(n % (a + b), a) + n / (a + b) * a << endl;
	return 0;
}

Compiler output:
a.cc:44:2: error: stray '#' in program
   44 | }#include <bits/stdc++.h>
      |  ^
a.cc:44:3: error: 'include' does not name a type
   44 | }#include <bits/stdc++.h>
      |   ^~~~~~~
a.cc:50:14: error: redefinition of 'const double PI'
   50 | const double PI = 3.141592653589793238;
      |              ^~
a.cc:7:14: note: 'const double PI' previously defined here
    7 | const double PI = 3.141592653589793238;
      |              ^~
a.cc:51:10: error: redefinition of 'const ll mod'
   51 | const ll mod = 1000000007;
      |          ^~~
a.cc:8:10: note: 'const ll mod' previously defined here
    8 | const ll mod = 1000000007;
      |          ^~~
a.cc:61:3: error: redefinition of 'template<class T> T lcm(T, T)'
   61 | T lcm(T a, T b)
      |   ^~~
a.cc:18:3: note: 'template<class T> T lcm(T, T)' previously declared here
   18 | T lcm(T a, T b)
      |   ^~~
a.cc:65:6: error: redefinition of 'void comb(std::vector<std::vector<long long int> >&)'
   65 | void comb(vector<vector<long long int>> &v)
      |      ^~~~
a.cc:22:6: note: 'void comb(std::vector<std::vector<long long int> >&)' previously defined here
   22 | void comb(vector<vector<long long int>> &v)
      |      ^~~~
a.cc:81:5: error: redefinition of 'int main()'
   81 | int main()
      |     ^~~~
a.cc:38:5: note: 'int main()' previously defined here
   38 | int main()
      |     ^~~~