//include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>

#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

#include <stdexcept>

using namespace std;

//conversion
//------------------------------------------
inline int toint(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class t> inline string tostring(t x) { ostringstream sout; sout << x; return sout.str(); }

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl
#define debug(x) cerr << #x << " = " << (x) << " (l" << __line__ << ")" << " " << __file__ << endl

// type alias
using ll = long long;
using ull = unsigned long long;

template<class ll>
inline ll getCeilExponent(ll a)
{
	if (a <= 0)
	{
		throw invalid_argument("vaule equal to or less than 0 should not be valid");
	}

	ll index = 0;
	--a;
	for (; a != 0; a >>= 1)
	{
		++index;
	}
	return index;
}

template<class ll>
inline ll getFloorExponent(ll a)
{
	if (a <= 0)
	{
		throw invalid_argument("vaule equal to or less than 0 should not be valid");
	}

	ll index = 0;
	a >>= 1;
	for (; a != 0; a >>= 1)
	{
		++index;
	}
	return index;
}

// computational complexity: o(log(max(a, b))) 
template<class ll>
inline ll getGcd(ll a, ll b)
{
	if (b == 0)
	{
		return a;
	}
	return getGcd(b, a % b);
}

// computational complexity: o(log(max(a, b))) 
template<class ll>
inline pair<ll, ll> getBezoutsIdentitySolution(ll a, ll b)
{
	if (b == 0)
	{
		return { 1, 0 };
	}
	auto sol = getBezoutsIdentitySolution(b, a % b);
	return { sol.second, sol.first - (a / b) * sol.second };
}

inline ll getModValue(ll a, ll m)
{
	return (a % m + m) % m;
}

// computational complexity: o(log(max(a, n))) 
inline ll getModInverse(ll a, ll m)
{
	auto sol = getBezoutsIdentitySolution(a, m);
	if (a * sol.first + m * sol.second != 1)
	{
		return -1;
	}
	return getModValue(sol.first, m);
}

ll getModPower(ll base, unsigned t, ll m)
{
	if (t == 0)
	{
		return 1ll;
	}

	auto res = getModPower(base, t >> 1, m);
	res = getModValue(res * res, m);
	if (t % 2 == 1)
	{
		res = getModValue(res * base, m);
	}
	return res;
}

template <class Integer>
class ResidueInteger
{
private:
	Integer mod_;
	Integer n_;
	static Integer global_mod_;

	// computational complexity: o(log(max(a, b))) 
	static inline pair<Integer, Integer> getBezoutsIdentitySolution(Integer a, Integer b)
	{
		if (b == 0)
		{
			return { 1, 0 };
		}
		auto sol = getBezoutsIdentitySolution(b, a % b);
		return { sol.second, sol.first - (a / b) * sol.second };
	}

public:
	Integer getModValue(const Integer& n) const
	{
		return (n % mod_ + mod_) % mod_;
	}

	// computational complexity: o(log(max(n, mod))) 
	inline Integer getModInverse(const Integer& n) const
	{
		auto sol = getBezoutsIdentitySolution(n, mod_);
		if (n * sol.first + mod_ * sol.second != 1)
		{
			return -1;
		}
		return getModValue(sol.first);
	}

	ResidueInteger() : mod_(global_mod_), n_(getModValue(0)) {}
	ResidueInteger(Integer n) : mod_(global_mod_), n_(getModValue(n)) {}
	ResidueInteger(Integer n, Integer mod) : mod_(mod), n_(getModValue(n)) {}

	inline ResidueInteger operator+(const ResidueInteger& rhs) const
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		return { this->n_ + rhs.n_, this->mod_ };
	}
	inline ResidueInteger operator+(const Integer& rhs) const
	{
		return { this->n_ + getModValue(rhs), this->mod_ };
	}
	friend inline ResidueInteger operator+(const Integer& lhs, const ResidueInteger& rhs)
	{
		return { rhs.getModValue(lhs) + rhs.n_, rhs.mod_ };
	}
	inline ResidueInteger& operator+=(const ResidueInteger& rhs)
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		this->n_ = getModValue(this->n_ + rhs.n_);
		return *this;
	}
	inline ResidueInteger& operator+=(const Integer& rhs)
	{
		this->n_ = getModValue(this->n_ + getModValue(rhs));
		return *this;
	}

	inline ResidueInteger operator-(const ResidueInteger& rhs) const
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		return { this->n_ - rhs.n_, this->mod_ };
	}
	inline ResidueInteger operator-(const Integer& rhs) const
	{
		return { this->n_ - getModValue(rhs), this->mod_ };
	}
	friend inline ResidueInteger operator-(const Integer& lhs, const ResidueInteger& rhs)
	{
		return { rhs.getModValue(lhs) - rhs.n_, rhs.mod_ };
	}
	inline ResidueInteger& operator-=(const ResidueInteger& rhs)
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		this->n_ = getModValue(this->n_ - rhs.n_);
		return *this;
	}
	inline ResidueInteger& operator-=(const Integer& rhs)
	{
		this->n_ = getModValue(this->n_ - getModValue(rhs));
		return *this;
	}

	inline ResidueInteger operator*(const ResidueInteger& rhs) const
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		return { this->n_ * rhs.n_, this->mod_ };
	}
	inline ResidueInteger operator*(const Integer& rhs) const
	{
		return { this->n_ * getModValue(rhs), this->mod_ };
	}
	friend inline ResidueInteger operator*(const Integer& lhs, const ResidueInteger& rhs)
	{
		return { rhs.getModValue(lhs) * rhs.n_, rhs.mod_ };
	}
	inline ResidueInteger& operator*=(const ResidueInteger& rhs)
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		this->n_ = getModValue(this->n_ * rhs.n_);
		return *this;
	}
	inline ResidueInteger& operator*=(const Integer& rhs)
	{
		this->n_ = getModValue(this->n_ * getModValue(rhs));
		return *this;
	}

	inline ResidueInteger operator/(const ResidueInteger& rhs) const
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		return { this->n_ * getModInverse(rhs.n_), this->mod_ };
	}
	inline ResidueInteger operator/(const Integer& rhs) const
	{
		return { this->n_ * getModInverse(getModValue(rhs)), this->mod_ };
	}
	friend inline ResidueInteger operator/(const Integer& lhs, const ResidueInteger& rhs)
	{
		return { rhs.getModValue(lhs) * rhs.getModInverse(rhs.n_), rhs.mod_ };
	}
	inline ResidueInteger& operator/=(const ResidueInteger& rhs)
	{
		if (this->mod_ != rhs.mod_)
		{
			throw invalid_argument("The mods of both operands should be equal.");
		}
		this->n_ = getModValue(this->n_ * getModInverse(rhs.n_));
		return *this;
	}
	inline ResidueInteger& operator/=(const Integer& rhs)
	{
		this->n_ = getModValue(this->n_ * getModInverse(getModValue(rhs)));
		return *this;
	}

	inline bool operator==(const ResidueInteger& rhs) const
	{
		return (this->n_ == rhs.n_) && (this->mod_ == rhs.mod_);
	}
	inline bool operator==(const Integer& rhs) const
	{
		return this->n_ == getModValue(rhs);
	}
	friend bool operator==(const Integer& lhs, const ResidueInteger& rhs)
	{
		return rhs.getModValue(lhs) == rhs.n_;
	}

	Integer getN() const { return n_; }

	friend std::ostream& operator<<(std::ostream& lhs, const ResidueInteger& rhs)
	{
		return lhs << rhs.n_;
	}

	friend std::istream& operator>>(std::istream& lhs, ResidueInteger& rhs)
	{
		lhs >> rhs.n_;
		return lhs;
	}
};
using rll = ResidueInteger<ll>;
ll mod = 998244353ll;
template<> ll rll::global_mod_ = mod;

template<class Integer>
class ResidueCombinatorialCalculator
{
private:
	Integer mod_;
	Integer n_;
	map<Integer, ResidueInteger<Integer>> values_;
public:
	ResidueCombinatorialCalculator(Integer n, Integer mod) : mod_(mod), n_(n)
	{
		values_[0] = ResidueInteger<Integer>(1, mod_);
	}

	ResidueInteger<Integer> calculate(Integer r)
	{
		if (r < 0 || n_ < r)
		{
			return 0;
		}

		if (values_.count(r) >= 1)
		{
			return values_[r];
		}
		if (values_.count(n_ - r) >= 1)
		{
			values_[r] = values_[n_ - r];
			return values_[r];
		}
		if (n_ < r * 2)
		{
			values_[r] = calculate(n_ - r);
			return values_[r];
		}

		values_[r] = calculate(r - 1) * (n_ - r + 1) / r;

		return values_[r];
	}
};
using rccll = ResidueCombinatorialCalculator<ll>;


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

	ll N;
	cin >> N;

	string S;
	cin >> S;

	vector<ll> Rs, Gs, Bs;
	Rs.reserve(N);
	Gs.reserve(N);
	Bs.reserve(N);
	for (ll i = 0; i < N * 3; ++i)
	{
		if (S[i] == 'R')
		{
			Rs.push_back(i);
		}
		else if (S[i] == 'G')
		{
			Gs.push_back(i);
		}
		else if (S[i] == 'B')
		{
			Bs.push_back(i);
		}
	}

	vector<ll> as(N), cs(N);
	vector<bool> is_bs(N * 3, true);
	for (ll i = 0; i < N; ++i)
	{
		ll a = min({ Rs[i], Gs[i], Bs[i] });
		ll c = max({ Rs[i], Gs[i], Bs[i] });
		as[i] = a;
		cs[i] = c;
		is_bs[a] = false;
		is_bs[c] = false;
	}

	rll res = 1;
	ll count = 0;
	for (ll i = 0; i < N * 3; ++i)
	{
		if (!is_bs[i])
		{
			continue;
		}
		res *= distance(as.begin(), upper_bound(as.begin(), as.end(), i)) - count;
		++count;
	}

	count = 0;
	for (ll i = N * 3 - 1; i >= 0; --i)
	{
		if (!is_bs[i])
		{
			continue;
		}
		res *= distance(upper_bound(cs.begin(), cs.end(), i), cs.end()) - count;
		++count;
	}

	for (ll i = 1; i <= N; ++i)
	{
		res *= i;
	}

	cout << res << endl;

	return 0;
}

Measured memory_bytes: 4628