var GET=(function(){function f(s){return new g(s);}function g(s){this._s=s.trim().split("\n");this._y=0;}g.prototype.a=function(f){var s=this._s, y=this._y, r;if(typeof s[y]==="string")s[y]=s[y].split(" ").reverse();r=s[y].pop();if(!s[y].length)this._y++;return f?r:+r;};g.prototype.l=function(f){var s=this._s[this._y++].split(" ");return f?s:s.map(a=>+a);};g.prototype.m=function(n,f){var r=this._s.slice(this._y,this._y+=n).map(a=>a.split(" "));return f?r:r.map(a=>a.map(a=>+a));};g.prototype.r=function(n,f){var r=this._s.slice(this._y,this._y+=n);return f?r:r.map(a=>+a);};return f;})();
var o=GET(require("fs").readFileSync("/dev/stdin","utf8"));
function xArray(v){var a=arguments,l=a.length,r="Array(a["+--l+"]).fill(0).map(x=>{return "+v+";})";while(--l)r="Array(a["+l+"]).fill(0).map(x=>"+r+")";return eval(r);}
var mod=998244353;

console.log(main());
function main(){
  var n = o.a();
  var s = o.a(1);
  var ans = 1;
  var n3 = n*3;
  var r = 0, g = 0, b = 0, rg = 0, rb = 0, gb = 0;
  for(var i = 0; i < n3; i++){
    if(s[i] === "R"){
      if(gb)ans = ans * gb-- % mod;
      else if(g)ans = ans * g-- % mod, rg++;
      else if(b)ans = ans * b-- % mod, rb++;
      else r++;
    }else if(s[i] === "G"){
      if(rb)ans = ans * rb-- % mod;
      else if(r)ans = ans * r-- % mod, rg++;
      else if(b)ans = ans * b-- % mod, gb++;
      else g++;
    }else{
      if(rg)ans = ans * rg-- % mod;
      else if(g)ans = ans * g-- % mod, gb++;
      else if(r)ans = ans * r-- % mod, rb++;
      else b++;
    }
  }
  for(i = 2; i <= n; i++)ans = ans * i % mod;
  return ans;
}