#include <iostream>
#include <string.h>
#include <stdlib.h>

using namespace std;

class Oracion {
public:
    char* a;
    Oracion();
    Oracion(const Oracion& o);
    Oracion& operator + (const Oracion& other);
    Oracion& operator - (const Oracion& other);
    Oracion& operator = (const Oracion& other);
    bool operator == (const Oracion& other);

    friend ostream& operator << (ostream& o, const Oracion& other);
    friend istream& operator << (istream& i, const Oracion& other);
};

Oracion& Oracion::operator = (const Oracion& other) {
    if (*this == other)
        return *this;
    char* aux = strdup(other.a);
    if (!aux) return *this;
    free(this->a);
    this->a = aux;
    return *this;
}

Oracion& Oracion::operator - (const Oracion& other) {
    size_t this_size = strlen(this->a);
    size_t other_size = strlen(other.a);
    size_t minimum_size = this_size > other_size ? this_size : other_size;

    size_t matches = 0;
    size_t removed = 0;
    for (size_t i = 0; i < minimum_size; i++) {
        if (this->a[i] != other.a[i]) {
            matches = 0;
            continue;
        }
        matches++;
        if (matches == other_size) {
            for (size_t j = 0; j < other_size; j++){
                this->a[i - j] == '*';
                removed++;
            }
            matches = 0;
        }
    }

    char* aux = (char*)malloc(sizeof(char) * (this_size - removed));
    if (!aux)
        return *this;
    size_t pos_actual = 0;
    for (size_t i = 0; i < this_size; i++) {
        if (this->a[i] != '*') {
            aux[pos_actual] = this->a[i];
            pos_actual++;
        }
    }
    aux[pos_actual] = '\0';
    free(this->a);
    this->a = aux;
    return *this;
}