View Code of Problem 43

#include "stdlib.h"
#include "algorithm"
#include "iostream"
#include <cstdio>
#include "string"
#include <iomanip>
#include <map>
#include <set>
#include "math.h"
using namespace std;
map<char, int> mp;
set<string> st;
int main()
{
	string str;
	cin >> str;
	int len = str.length();
	for (int i = 0; i < len; i++)
	{
		if (('a' <= str[i] && str[i] <= 'z') || ('A' <= str[i] && str[i] <= 'Z'));
		else
		{
			str.erase(str.begin()+i);
			i--;
		}
		len = str.length();
	}
	cout << str<<endl;
	return 0;
}