import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop, core.stdc.stdio;

alias Mint = ModInt!(998244353);

void main() {
    auto N = readln.chomp.to!int;
    auto S = readln.chomp;

    int r, g, b, rg, gb, br;
    auto ans = Mint(1);

    foreach (c; S) {
        if (c == 'R') {
            if (gb) {
                ans *= gb;
                gb -= 1;
            } else if (g) {
                ans *= g;
                g -= 1;
                rg += 1;
            } else if (b) {
                ans *= b;
                b -= 1;
                br += 1;
            } else {
                r += 1;
            }
        } else if (c == 'G') {
            if (br) {
                ans *= br;
                br -= 1;
            } else if (r) {
                ans *= r;
                r -= 1;
                rg += 1;
            } else if (b) {
                ans *= b;
                b -= 1;
                gb += 1;
            } else {
                g += 1;
            }
        } else {
            if (rg) {
                ans *= rg;
                rg -= 1;
            } else if (g) {
                ans *= g;
                g -= 1;
                gb += 1;
            } else if (r) {
                ans *= r;
                r -= 1;
                br += 1;
            } else {
                b += 1;
            }
        }
    }

    foreach (i; 1..N+1) ans *= i;
    ans.writeln;
}

// This implementation of ModInt references https://github.com/yosupo06/dunkelheit/blob/master/source/dkh/modint.d

// Manually verified on: https://yukicoder.me/problems/no/117
// Manually verified on: https://atcoder.jp/contests/cpsco2019-s3/tasks/cpsco2019_s3_f

struct ModInt(uint mod) {
    import std.conv : to;

    uint n;

    this(int n) {
        this.n = (n % mod + mod) % mod;
    }

    this(long n) {
        this.n = (n % mod + mod) % mod;
    }

    private this(uint n) {
        this.n = n;
    }

    string toString() const {
        return to!string(this.n);
    }

    private uint normilize(uint n) const {
        return n < mod ? n : n - mod;
    }

    private ModInt pow(uint n, long x) const {
        long ret = 1;
        long a = n;
        while (x) {
            if (x & 1) ret = ret * a % mod;
            a = a * a % mod;
            x >>= 1;
        }
        return ModInt(to!ulong(ret));
    }

    ModInt opBinary(string op : "+")(ModInt rhs) const {
        return ModInt(normilize(n + rhs.n));
    }

    ModInt opBinary(string op : "-")(ModInt rhs) const {
        return ModInt(normilize(n + mod - rhs.n));
    }

    ModInt opBinary(string op : "*")(ModInt rhs) const {
        return ModInt(to!uint(to!long(n) * rhs.n % mod));
    }

    ModInt opBinary(string op : "/")(ModInt rhs) const {
        return this * pow(rhs.n, mod-2);
    }

    ModInt opBinary(string op : "^^")(ModInt rhs) const {
        return pow(this.n, rhs.n);
    }

    ModInt opBinary(string op, T)(T rhs) const {
        ModInt mod_rhs = ModInt(rhs);
        return opBinary!op(mod_rhs);
    }

    ModInt opOpAssign(string op)(ModInt rhs) {
        return mixin ("this=this"~op~"rhs");
    }

    ModInt opOpAssign(string op, T)(T rhs) {
        return mixin ("this=this"~op~"rhs");
    }
}
