#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>

using namespace std;

int main()
{
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);

	int hlpr,ksp,klet,i;
	string x;
	ksp = 0;
	klet = 0;
	while (getline(cin, x)) {
		for (i = 0; i < x.length(); i++) {
			if (((int)x[i] > 96 && (int)x[i] < 123)||((int)x[i] > 47 && (int)x[i] < 58)) {
				klet = klet + 1;
				if (ksp != 0 && ksp > 1) { x.erase(i-ksp, ksp-1); i = i - ksp; }
				ksp = 0;
			}
			else
				if ((int)x[i] > 64 && (int)x[i] < 91) {
					hlpr = (int)x[i] + 32;
					x[i] = (char)hlpr;
					klet = klet + 1;
					if (ksp != 0 && ksp > 1) { x.erase(i - ksp, ksp-1); i = i - ksp; }
					ksp = 0;
				}
				else
					if ((int)x[i] == 32) {
						ksp = ksp + 1;
						if (klet != 0 && klet <= 3) { x.erase(i - klet, klet + 1); i = i - klet-1; };
						klet = 0;
					}
					else {
						x.erase(i,1);
						if (ksp != 0 && ksp > 1) { x.erase(i - ksp, ksp-1); i = i - ksp; }
						ksp = 0;
						i--;
					}
  		}
		if (klet != 0 && klet <= 3) { x.erase(i - klet , klet + 1); i = i - klet - 1; };
		klet = 0;
		ksp = 0;
		cout << x << endl;
	}

	return 0;
}