Begin1. Given the side of the square \(a\). Find its perimeter \(P = 4 \cdot a \).

**Solution in Python 3:**

a = int(input("Enter the side of the square (a): "))

P = 4*a

print("Perimeter P: ", P)

**Solution in C++:**

#include <iostream>

using namespace std;

int main(){

double a, p;

cout << "Enter the side of the square (a): ";

cin >> a;

p = 4*a;

cout << "Perimeter: " << p;

return 0;

}